While today's engagement's only correspond to dating in a halachic sense, there is a process called Kiddushin which is the halachic act of engagement. Once a woman is halachically engaged (mekudeshet), she may not marry anyone else unless she receives a halachic divorce (get) or if her husband dies. If the husband dies without children, in certain cases, there is a mitzvah of Chalitza prior to remarrying.
- 1 Ritual Results of Kiddushin
- 2 Procedure of Kiddushin
- 3 The Beracha for Kiddushin (Birkat Erusin)
- 4 Nesuin before Kiddushin
- 5 Sources
Ritual Results of Kiddushin
- Once a woman is halachically engaged, it is an extremely serious sin to have relations with anyone else. Not only that, there are numerous safeguards some of which are Biblical and some of which are rabbinic which prevent a married woman from becoming too close with another man. These apply equally to a married and halachically engaged woman.
Procedure of Kiddushin
- Kiddushin in theory could be accomplished in one of three ways: using money, a written document, or through marital relations. However, accomplishing Kiddushin through marital relations is a deplorable practice and is strictly forbidden.
- The minhag is to accomplish Kiddushin with money as opposed to a written document. 
- According to a minority opinion, chupa can also accomplish Kiddushin. Some Achronim are concerned for this opinion.
Giving the Ring and Saying Harei At Mekudeshet Li
- The minhag is to do Kiddushin with a ring.
- Immediately after reciting the beracha on the wine and the Birkat Erusin, the chattan should recite ”הרי את מקודשת לי בטבעת זו כדת משה וישראל” and put the ring on the finger of the kallah in the presence of two valid witnesses. 
- If he gave her the ring before saying the statement, she should return the ring and do it again correctly. After the fact, even if they didn’t redo it, the Kiddushin is valid.
Laws of the Ring
- According to most poskim, it is permitted to effect Kiddushin with a borrowed ring if the person you are borrowing it from knows that you’re using it for Kiddushin. However, to avoid a dispute one should borrow the ring from the third party as a matana al menat lhachzir (a gift given on condition that it is later returned).
- If the ring gets lost, it is possible to do the Kiddushin with a coin.
- The ring must belong exclusively to the chattan. Therefore, the practice is that the Mesader Kiddushin asks the chattan if the ring belongs to him.
- One should use a plain ring without any stones or designs, so that the kallah does not misevaluate the value of the ring. The custom is to confirm with the witnesses that the ring is worth a perutah to show that she is getting married on only a perutah. Nonetheless, initially one should avoid any question by using a plain ring. 
- Some have the minhag to use a silver ring, while others prefer to use a gold ring. Either is certainly acceptable, but if the ring is silver, the man must tell her so, otherwise she will assume it is gold, and it is questionable if the Kiddushin is effective.
- The ring should be placed on the right index finger of the kallah. If it is placed on the left hand, the Kiddushin is certainly still valid.
Double Ring Ceremony
- The performance of a double ring ceremony, where in addition to the chattan giving the kallah a ring, the kallah gives a ring to the chattan as well, should be strongly discouraged, even if the kallah does not say anything.
Removing Other Jewelry
- Some have the minhag for the chattan and kallah to remove all jewelry before the chuppah. Others think this is unnecessary. Some think that by giving away one’s personal belongings to his friend before going to the chuppah it is some sort of segula. In reality, there is no such segula, but one may do so, since the friend will make sure that it is watched properly.
- Some say it is preferable not to do kiddushin at night.  During the winter this is usually impractical.
Selecting Edim (Witnesses) for Kiddushin
Witnesses (eidim) are necessary to observe the Kiddushin process, when the chosson gives the kallah a ring and says “harei at mekudeshet li betaba’at zu kedat Moshe veYisrael.”
- It is proper to specify witnesses for the Kiddushin. However, if a mistake occurred and the witnesses were invalid, the marriage is valid as long as other kosher witnesses were watching.
- Some hold that it is critical for the witnesses to see the bride's face at the time of the Kiddushin. However, in some communities as a matter of modesty (tzeniyut) the bride's face isn't uncovered.
Who is a Kosher Witness
- Relatives cannot be eidim for the chosson and kallah nor can the eidim be related to each other. 
- A gambler, someone who collects interest, and someone who profits from produce produced during shemita are examples of invalid witnesses in general and specifically for Kiddushin.
The Beracha for Kiddushin (Birkat Erusin)
ברוך אתה ה' אלקנו מלך העולם אשר קדשנו במצותיו וצונו על העריות ואסר לנו את  הארוסות והתיר לנו את הנשואות לנו על ידי חופה ב\וקידושין ברוך אתה ה' מקדש עמו ישראל על ידי חופה ב\וקידושין
- One should make the Beracha before giving the Kallah the ring.
- The Minhag is that the Mesader Kiddushin is the one who makes the Beracha.
- One should make Birkat Erusin over a cup of wine. If there is no wine available, one may use Shechar. If there is neither wine nor Shechar available, one may make Birkat Erusin without them. 
Nesuin before Kiddushin
- Is it possible to have a Nesuin before Kiddushin? It is a major dispute in the Achronim.
- See Mishna Brurah 493:3
- Kiddushin 2a, Rambam (Ishut 1:2). Rav Hershel Schachter in B’ikvei Hatzon p. 195 writes that Kiddushin establishes a woman as a married woman not yet in her husband’s domain (eshet ish shelo b’bet habaal), while Nesuin give her the status of a married woman living in her husband’s domain (eshet ish b’bet habaal).
- Mishna Kiddushin 2a, Rambam (Gerushin 1:1)
- Rambam (Yibum 1:2)
- Vayikra 20:10, Rambam (Ishut 1:3)
- With regards to Yichud, see Avoda Zara 36b. Regarding the numerous other separations between men and women, such as touching, staring inappropriately, speaking together inappropriately, listening to her voice, or even thinking about her inappropriately, see the Appropriate Interaction between Men and Women page.
- Mishna Kiddushin 2a, Rambam (Ishut 1:2), Shulchan Aruch 26:4
- The Gemara Kiddushin 12b records Rav's insistence on not accomplishing Kiddushin with marital relations that he would give lashes to anyone who did such. Rashi (s.v. derav) and Rambam (Ishut 3:21) explain that the reason it is deplorable is because it is licentious. Shulchan Aruch EH 26:4 codifies this as halacha.
- Rambam (Ishut 3:21). Rav Schachter in a shiur on YUTorah ("Hilchos Siddur Kiddushin", min 4) explained that the reason we do so is because we are registering our compliance with chazal and disagreement with the karaites who didn't accept Kiddushin through money. Nitai Gavriel (Nesuin v. 1, p. 24-5) offers kabbalistic reasons for why we do Kiddushin with money as opposed to a written document.
- Rav Huna in Kiddushin 5a holds that chupa can accomplish Kiddushin based on a kal vechomer. While the Rabbenu Chananel holds like Rav Huna, most rishonim do not. See Rosh (Kiddushin 1:1) and Shulchan Aruch 26:2.
- Pitchei Teshuva 21:3 quotes the Shaar Hamelech who is very concerned for the opinion of Rabbenu Chananel claiming that this is also the opinion of Rashi and the Tur. This has relevance if someone did an invalid Kiddushin with kesef but used the chupa as Kiddushin whether the woman would need a get to remarry. Aruch Hashulchan 26:15 is similarly concerned.
- Shulchan Aruch 31:2, Yalkut Yosef (Sovah Semachot 1:7:14). Rav Hershel Schachter (Hilchos Siddur Kiddushin 4:00) explained that the reason this minhag developed was to show our compliance with Chazal as opposed to the Karaites who didn't accept Kiddushin through money. Nitei Gavriel (Nesuin v. 1, p. 24-5) offers kabbalistic reasons for why we do Kiddushin with money specifically.
One can technically use any item that is worth a perutah (25 mg of silver according to Shiurei Torah (3:42)). Although Rabbi Eli Mansour Syrian Sephardic Wedding Guide writes that the practice in the Syrian community is to use an actual coin (in which case you would say בכספא הדין instead of בטבעת זו), Yalkut Yosef (Sova Semachot 1:7:14) writes that the common practice is to use a ring. HaNesuin Kihilchatam 7:5 agrees. The Sefer Hachinuch (Mitzvah 554) adds that a reason to use a ring is so that it should serve as a reminder to her always of her marriage. See Yalkut Yosef for mystical and other reasons.
- < This is the position brought in Shulchan Aruch EH 34:1 because the Rif (Shu"t 293) and Rambam (Hilchot Ishut 3:23) hold that the Birkat Erusin is a birkat hamitzva. Therefore, it must be made over le’Asiyatan, before the Kiddushin. Otherwise, it would be a beracha levatala. Rabbenu Tam (Pesachim 7a “Biliva’er) and other Rishonim argue that it is a birkat hashevach and should be recited after the Kiddushin. Although the opinion of the Rosh is subject to debate, the Beit Yosef (34:1b) assumes that the Rosh holds like the Rif.
- Sefer Hamakneh (Kuntres Acharon 27:3) writes that you should be careful to recite the full “harei at” before placing the ring on her finger. Haisuin Kihilchatam 7:38 and Yalkut Yosef (Sova Semachot 1:7:8) agree. If one gave the ring before reciting the “harei at” they should give the ring again after reciting it. Yabea Omer EH 2:5:3 concludes that the same ring can be used the second time. See also Rabbi Aryeh Lebowitz (Ten Minute Halacha: Saying Harei at Mekudeshes After Giving the Ring)
- <Yalkut Yosef (Sova Semachot 1:7:1). According to many authorities, the witnesses must see the chatan place the ring on the kallah's finger (Shu”t HaRashba 1:780, Rama EH 42:4). Although some authorities rule that this is not essential, the accepted practice is to be certain that the witnesses see the actual placing of the ring on the kallah's finger (Pitchei Teshuvah EH 42:12, Hanishuin Kihilchatam 8:12).
- Yalkut Yosef (Sovah Semachot 1:7:8) writes that it is important to say the hari at before giving the ring otherwise it is like getting married with a loan which is ineffective. If this happened he should take back the ring, say the hari at, and then give her the ring again. Yabia Omer EH 2:5:3 proves from Rama 27:3 that it is enough to just repeat the hari at and give the ring again and not to have to use a new ring. Rabbi Mordechai Willig (4th Year Halacha Hilchos Ishut 5) agrees that if he gave the ring first he should take it back and repeat it. Once the chatan said the words “hari at mikudeshet li” even though he didn’t finish the whole phrase the chatan should take back the ring and do it again.
- The Rosh (Kiddushin 1:20) explains that if a man uses a borrowed ring it is effective because even though the ring doesn’t belong to him it isn’t similar to something stolen since he is giving her the benefit of having the ring for some short period of time. Furthermore, the Rosh adds that if a person asks explicitly to borrow a ring in order to marry a woman he is clearly intending to use whatever language it is necessary to get married and so it is as though he meant to acquire the ring from the third party with a matana al menat lhachzir which is effective. However, according to this approach it is critical that he either pay his wife for the ring and return it or he return the value of the ring to the third party. He cites that this was also the opinion of the Rav Moshe Hacohen and Rabbenu Shimshon. The Shulchan Aruch EH 28:19 adopts the opinion of the Rosh. Chelkat Mechokek 28:33 writes that according to the Rosh’s second approach if a person used a borrowed ring and didn’t return it or pay for it afterwards the Kiddushin is invalid retroactively. Furthermore, Bet Shmuel 28:48 clarifies that if the man didn’t tell the lender that he is using it for Kiddushin it would only work according to the first approach, which is acceptable under certain conditions that he delineates there.
- The Rashba 1:273 argues that a borrowed ring is ineffective since it doesn’t belong to the man. The Avnei Nezer EH 136 is very concerned for the opinion of the Rashba. See Yabia Omer EH 6:6 regarding using this as a factor in invalidating a Kiddushin. Therefore, to avoid a dispute one should make sure to use a matana al menat lhachzir which is effective as the Shulchan Aruch EH 28:20 writes.
- Pitchei Teshuva 27:1 cites the Bet Shmuel who held that initially one shouldn’t use a coin based on the gemara Bava Metsia 46a, but the Avnei Meilum argues that only for chalipin where the kinyan requires something that can have a lasting value is a coin ineffective.
- Shulchan Aruch EH 28:1, Yalkut Yosef (Sova Semachot 1:7:12), HaNisuin Kihilchatam 7:14. Rav Eliyahu Ben Haim (How to Perform a Wedding Ceremony Part 2/2) 0:50 explains that he could have bought it or received it as a gift, as long as it is entirely his and not borrowed (Though Shulchan Aruch 28:17 holds that if it is borrowed, it would work bidieved as long as you notified the person you were borrowing from that you intended to use it for Kiddushin. See also Yabea Omer 6:6:7). Beit Shmuel 29:46 writes that it is the responsibility of the mesader Kiddushin to clarify this. Rabbi Aryeh Lebowitz (Ten Minute Halacha: The Chuppah Part 2) quotes Rav Schachter that you should ask this before the birkat erusin to minimize the pause between the beracha and giving the ring.
- Tosafot Kiddushin 9a s.v. “Vihilchita,” Shulchan Aruch EH 31:2, Yalkut Yosef (Sova Semachot 1:7:15), Nitei Gavriel 21:5, HaNisuin Kihilchatam 7:7, Rabbi Aryeh Lebowitz (Ten Minute Halacha: The Chuppah Part 2)
- Rama EH 31:2, Ben Ish Chai (Parashat Shoftim: Halacha 5), Yalkut Yosef (Sova Semachot 1:7:12), HaNisuin Kihilchatam 7:30, Rabbi Eli Mansour
- The Aruch Hashulchan 31:8 comments that even though the kallah has a veil over her head to indicate that she accepts the ring whatever it is worth we should avoid such a shaylah by using a plain ring because of possible concerns.
- Ben Ish Chai Parashat Shoftim Halacha 8, Yalkut Yosef (Sova Semachot 1:7:16)
- Mordechai Kiddushin 488, HaNisuin Kihilchatam 7:6, Otzar Haposkim 10: pg. 364
- Rav Eliyahu Ben Haim (How to Perform a Wedding Ceremony Part 2/2) 3:00
- Nisuin K’halacha 7:6. Rama 31:2 writes that if he gives her a ring that is copper and lies that it is gold there is a safek Kiddushin.
- Maharam Mintz 109, Yalkut Yosef (Sova Semachot 1:7:17), HaNisuin Kihilchatam 7:23, Rabbi Aryeh Lebowitz Ten Minute Halacha: The Chuppah Part 2), Rav Eliyahu Ben Haim (How to Perform a Wedding Ceremony Part 2/2) 3:30, Rabbi Eli Mansour.
- Rav Moshe Feinstein (Iggerot Moshe EH 3:18) writes that this practice is improper, for two reasons. First, it is a violation of the prohibition against imitating the practices of non-Jews. Secondly, conducting a double ring ceremony could lead to a fundamental misunderstanding of the entire construct of Kiddushin, as people will mistakenly think that the Kiddushin depends upon the transfer of rings from both the chattan to the kallah and the kallah to the chattan. Nevertheless, he concludes that the Kiddushin is still valid if this was done after the chattan already gave the ring and said the “harei at.” Rav Eliyahu Ben Haim (How to Perform a Wedding Ceremony Part 2/2) 7:35 agrees. See however, Rav Osher Weiss (Minchas Asher 1:71, 3:98) who believes that this Kiddushin would be invalid. Rabbi Eli Mansour writes that if the kallah also wishes to give a ring to the chattan, this should be done after the chuppa, and not as part of the ceremony. Regarding the general halacha when it comes to men wearing wedding bands, see Rabbi Aryeh Lebowitz (Ten Minute Halacha: Men Wearing Wedding Bands).
- Shulchan Haezer vol. 2 pg. 137. Different explanations are given for this. Rav Soloveitchik (Nefesh Harav pg. 256) explained that this practice is a zecher lachurban. This is based on the Mishna in Sota 49a which speaks of a certain rabbinic decree in the times of the Roman empire to ban the kallah and chattan from wearing certain crowns in order to minimize our feelings of joy.
- Rav Eliyahu Ben Haim (Rav Eliyahu Ben Haim (How to Perform a Wedding Ceremony Part 2/2) ) 6:00
- Halachically Speaking Vol 4 Issue 12 quoting Rav Yisrael Belsky
- Beer Heitev EH 26:4 quoting the Reem and Knesset HaGedola. See also Tosfot Ketubot 2a s.v. LeYom.
- Rav Schachter Ketubot shiur 54 (min 30-7) said that it is recommended to get married during the day, but during the winter it is impractical and personally his wedding (officiated by Rav Moshe Feinstein) was during the winter and during the night.
- * This is based on the Mishna Makkot 5b which establishes that if there is a group of onlookers of a case, they are all considered eidim for that case. If there are two relatives in that group of onlookers, then their eidus is passul because two relatives cannot be eidim together for a certain case. The Ritva (Makkot 6a d"h "Lemechzi") quotes some who hold that there is problem if family is present at the chuppa and there is no explicit designation of specific eidei Kiddushin. The eidim for Kiddushin are eidei kiyum, which means that their viewing of the act of Kiddushin is in itself the establishment of Kiddushin. Therefore, anyone that watches the Kiddushin process are considered eidim, which causes a problem when there are relatives in the room watching the Kiddushin. In order to resolve this problem, one can designate two specific eidim who are not relatives to the exclusion of all others in the room, thus avoiding any potential kerovim from becoming eidim and invalidating the Kiddushin. The Ritva himself disagrees with this opinion.
- The Rosh Makkot 1:11 argues with this entire premise, and says that the only time that invalid eidim disqualify the group is when they are required to testify in court. However, by Kiddushin, there is no testimony in court, so there is no potential invalid witnesses in the first place. Thus, there is no requirement whatsoever to designate specific witnesses to the exclusion of others. This is based on the fact that he holds that eidei Kiddushin are eidei kiyum, and not eidei re’iya.
- Nefesh HaRav (p. 261) quoting Rav Soloveitchik says that it is proper to specify edim but if one didn't the kiddushin is valid if there were other edim there. Nitai Gavriel (Nesuin vol. 1 20:5, p. 140) agrees and adds that it is a wise idea to specify edim so that they pay attention to watch the kiddushin. See Chatom Sofer EH 100 and Achiezer EH 27. See also From_The_Rabbi's_Desk_-_Wedding_Questions by Rabbi Aryeh Lebowitz.
- Pitchei Teshuva EH 31:5
- Rama EH 31:2, Nitai Gavriel (Nesuin v. 1, 20:10, p. 141)
- There is a discussion as to which type of relatives cannot serve as eidim. The psak is that although strictly speaking only a rishon be’rishon, a sheni be’sheni, or a shlishi beshlishi cannot serve as eidim, we are machmir that even a revi’i berevi’i should not serve as eidim. These terms describe how many generations removed the relation is. For example, a rishon berishon are siblings because their parents are one generation above them and are the cause of the relation between them. A sheni besheni are first cousins, because their grandparents are the common ancestor, who are the source of their relation. So we say that shlishi beshlishi is not permitted to be eidim together, which are three generations removed from the source of their relation, and we are machmir to not even allow revi’i berevi’i to be eidim together, which are four generations removed from the source of their relation. Even if someone married into the family and is not related by blood, they are still not permitted to serve as eidim for the chasan and kallah. See Wedding Questions] by Rabbi Aryeh Lebowitz
- Mishna Sanhedrin 24b. The Gemara explains that all of these fall under the category of theft because people who violate laws when it comes to money cannot be trusted in telling the truth in general.
- The Rambam's text (Hil' Ishut 3:23) reads והבדילנו נן העריות, and it is quoted in the Beit Yosef (34:1), but not Shulchan Aruch.
- The Peri Megadim (34:1) points out that the word את does not appear in Shulchan Aruch (34:1), though it does appear in the Gemara (Ketubot 7b), Tur, and all the Siddurim.
- The Ran (Ketubot 7b) quotes Rabbeinu Tam who took out the word נשואות, since this is only Erusin and not Nissuin. He brings Rav Hai Gaon who says that this is also the Minhag of the two Yeshivot in Bavel. The Hagahot Asheri (Ketubot 1:12) quotes the Mordechai in the name of R' Ephraim who says the Minhag is to say it. In Shulchan Aruch (34:1), Maran paskens to say it.
- The Ran (Ketubot 7b) quotes the Baal HaIttur that the proper text of the Beracha is בקידושין and not וקידושין. The mistake arose because in this case they're pronounced the same way and people confused the two. His opinion is quoted by the Beit Yosef (34:1) and incorporated into Shulchan Aruch. The Chelkat Mechokek (34:2) also quotes this opinion. The Rama writes that their Minhag is to say וקידושין.
- The Ramban (Ketubot 7b) says that in order for the conclusion of the Beracha to match the opening and because we're only doing Nissuin now and not Erusin, we should only conclude מקדש עמו ישראל and not add על ידי חופה וקידושין. He claims that Rav Hai Gaon also said the Minhag in the Bavli Yeshivot was not to and that he found a manuscript of the Rif with the words crossed out. The Ramban is quoted in the Rosh (1:12), Ran (ibid.), Tur (34:1), and Beit Yosef (ibid.). The Rambam also does not have those words, and the Shulchan Aruch also paskens that way. The Rama says the Minhag is to say it. It seems that many modern day Sepharadic Siddurim (Kavannat HaLev, Birkat Rafael, Succat David) also have it.
- The Hagahot Maimoniot (Hil' Ishut 3:60) quotes the Hagahot of Rabbeinu Peretz on the Smak who says that Rabbeinu Yechiel MiParis would have the Chattan say the Beracha of לקדש האשה, based on the Yerushalmi Berachot 9:3.
- Like all Birkot HaMitzvah, the Beracha must be made before doing the Mitzvah (Pesachim 7b). The Rif (Sh"T 293) and Rambam (Hilchot Ishut 3:23) write that it would be a Bracha Levatala to make the Beracha after the Kiddushin. However, many Rishonim, including Rav Shererah Gaon (Tur 34:4), Tosafot beShem Rabbeinu Tam (Pesachim 7b), Rashba (Ketubot 7b), Raavad (ibid.), She'etot (16), Tosafot Rid (Ketubot 7a), Tosafot HaRosh (Pesachim 7b), Maggid Mishneh (who really agrees with the Rambam, but says the Minhag is not like him), and Ramach, hold that one should make the Beracha afterwards, as it's a Birkat HaShevach. Additionally, it's Teluya beDaat Acherim, meaning that it depends on the woman agreeing, so, if she doesn't, one just made a Beracha Levatala.
- The Rosh (Ketubot 1:12) first brings the opinion of the Rif that one must make the Beracha before, but he then brings the latter opinion and doesn't explicitly take sides. On the other hand, In his Teshuvot (Klal 26) he explicitly sides with the Rif. The Korban Netanel (2) suggests that the Rosh must really hold like the Rif, but brought the latter opinion to indicate thar if one did forget to make the Beracha before the Kiddushin, there is what to rely on to make it afterwards. The Beit Shmuel (34:4) and Chelkat Mechokek (34:2) both assume like this, as well, though they make no reference to the Rosh.
- The Beit Yosef (34:1b) assumes that the Rosh holds entirely Rif; therefore, since all three Amudei HaHoraah (pillars of halacha) agree, this is the position he writes in Shulchan Aruch (34:1). The Bach takes issue with the Beit Yosef's understanding of the Rosh, as the Rosh himself (later, in 1:17) brings the opinion of Rav Nissim Gaon that one can still make Birkat Erusin up until the Nissuin. The Chiddushei Hagahot (on that Beit Yosef, printed in the Shirat Devorah Tur) raises an important issue in Kllalei HaPesak. He refers to the Kllal brought by the Tur (CM 72) that when faced with a contradiction between the Piskei haRosh and the Teshuvot HaRosh, we follow the Pesakim, so the Shulchan Aruch should've taken this into account. However, the Beit Yosef himself doesn't agree to the rule (YD 169; 201), and it's not totally clear that the Rosh changed his mind in the Pesakim. Additionally, there is little to no practical ramification, as it would be a Machaloket Amudei Horaah of 2 vs. 1, where he would just pasken against the Rosh. See further Sh"t Rambam 101, Rambam Hilchot Berachot 5:5, Sh"t Tashbetz (2:27), Meiri (Pesachim 7b), and Hagahot Rabbi Akiva Eiger (YD 19:1).
- As referenced above, there are a number of Rishonim who were of the opinion that one may make the Birkat Erusin until the Nissuin, as the Biblical permissibility of one to his wife accomplished through the Erusin has not yet ended, similar to one's ability to make Birkat HaMazon as long as the food has not been fully digested in his body. Those Rishonim include the Hagahot Maimoniot (Hil' Ishut 3, 60), Hagahot Asheri (Ketubot 1:12), Rav Nissim Gaon and Rabbeinu Yonah (quoted in the Rosh Ketubot 1:17, Tur 34), the Rivash (responsa 82), Mordechai (Ketubot 1:131), Rama (34:1). See Mishneh LeMelech (Hil' Ishut 3). As it does "look" like a Beracha Levatala, when one makes Birkat Erusin at Nissuin, some Rishonim (Sh"t HaRivash 88, R' Peretz quoted in Beit Yosef 34:3, See Darkei Moshe 34:6) suggest redoing the Maaseh Kiddushin. Others even say one should repeat the Beracha (Rabbeinu Nissim quoted in Beit Yosef 34:3, Kol Bo quoted in Darkei Moshe 34:6,7), especially if he did the original Kiddushin through a Shaliach. The former Rishonim said that would be a Beracha Levatala, and one should only say the Beracha without Shem uMalchut. The Rama (34:4) paskens like the Rivash.
- The Rama (34:1) writes that even though when one does a Mitzvah himself and not through a Shaliach he makes the Beracha himself, in order not to embarrass one who does not know how to make a Beracha, the Minhag developed that someone else makes the Beracha.
- With regards to making Birkat Erusin via a Shaliach, See Tosafot Ketubot 7b and Tur 34:1 who says the Shaliach makes the Beracha. The Rambam (Hil' Ishut 3:23) says that either one may makes the Beracha. Shulchan Aruch (34:1) sounds like one makes the Beracha himself regardless, and there the Rama makes his above comment. See Magen Avraham OC 432:6, Meiri beginning of second Perek of Kiddushin, Darkei Moshe (34:7, 35:1, and 62:7).
- Rambam (Hil' Ishut 3:24), Maggid Mishneh (ibid.), Shulchan Aruch 34:2, Darkei Moshe 34:7. This is only true by Birkat Erusin, not Sheva Berachot
- The Masat Binyamin (responsa 90), student of the Rama, writes that it is obvious that chupa is ineffective before Kiddushin. The Bet Shmuel 64:6 adopts this view. The Mishna L’Melech (Ishut 10:2), however, argues because the Ramban (Kiddushin 10a s.v. veha), Rashba (s.v. iy), Ritva (s.v. iybaya) clearly hold that chupa is effective even if the Kiddushin only takes place afterwards. Rav Yohanatan Eibishitz in Bnei Ahuva (Ishut 10:2) answers for the Masat Binyamin, though he favors the opinion of the Mishna Lemelech. See further Pitchei Teshuva EH 61:1. Of interesting note is the Mordechai (Ketubot no. 132) who explains the text of the sheva brachot “chupa v’Kiddushin” to indicate that the order is of no consequence.