The practice of standing as the chatan and kalla walk past those who are seated is a relatively new phenomenon. The traditional approach to new practices in a religious setting is to be wary of them, for several reasons. One reason is that some new practices are against the spirit or even the letter of Halacha or Jewish thought. Another is that new practices create confusion, as it is difficult to distinguish between important minhagim, which one should (preferably) keep and from which one can learn and gain, and spiritually meaningless practices. A third dimension is a feeling many have that if the practice in question is a proper one, generations before us would have initiated it. A related idea is that initiating a new minhag gives the impression of arrogance and dismissal, as if to say: “We know better than our predecessors.”
Let us analyze the practice of standing for the chatan and kalla in light of the above. It is difficult to find anything significantly objectionable about standing for a chatan/kalla. Although some people may be irked by the tendency toward attributing special powers to the chatan and kalla,[4] there are a staggering number of sources that indicate that the idea of standing is generally appropriate. After all, we are commanded to stand for various people whom we are required to honor,[5] and we find numerous sources about giving great regard to the chatan/kalla. These include such halachot as halting Torah study to escort the kalla and giving precedence to a wedding procession over a funeral procession.[6] One could argue that these reflect a mitzva to make them happy rather than to honor them per se. However, numerous sources[7] refer to kavod (honor) for them and compare it to the kavod due to others.
There are different ways of showing kavod to different people. For example, a husband and wife should honor each other greatly,[8] yet we do not find a halacha that they should stand for each other. The main honor for a chatan and kalla is acting in a manner that expresses interest in and excitement about their marriage and future home. Certainly, it is more appropriate to sit in rapt attention than to rise while continuing to talk to a friend. However, standing would also seem to be a reasonable expression of honor.
Some people quote the concept of chatan domeh l’melech (a groom resembles a king) as grounds for standing. This phrase is found in the Pirkei D’Rabbi Eliezer,[9] along with examples of similarities between a chatan and a melech: They both are praised for seven days; they wear nice clothing; they are involved in partying (regarding a chatan, for seven days, and some understand this to mean that he may not go to work); they do not go in the street alone. The latter two points are brought as halacha in the Rama.[10] The gemara[11] makes another interesting comparison: A chatan is like a kohen, and he therefore sits at the helm. However, we did not find a classical source requiring standing before a chatan.
There are semi-classical sources that speak about standing for the chatan as he goes to get an aliya during the week before and after the wedding.[12] The lack of similar sources about standing specifically on the way to the chupa should not be surprising, as for hundreds of years, weddings were held outside and indications (including in old paintings) are that seating was not the norm.
In summation, we find nothing compelling to require standing for the chatan/kalla, but we agree that it has some logic and is not intrinsically objectionable. Out of respect for our predecessors who did not do so, we would not have initiated the practice, but out of respect for present-day peers who do it (and perhaps chatanim/kallot who already expect it), we encourage joining along.