The very last verse in Parshas Toldos tells us that Esav, after realizing that his parents disapproved of his Canaanite wives, went and married “Machlas, the daughter of Yishmael”.

The Midrash, as well as the Yerushalmi (Bikurim 3:3) question this from the verse (36:3) which reports the wife of Esav being Basmas the daughter of Yishmael? Chazal answer that we see from this that although her name was Basmas, she was called Machlas, because on the day that he got married all of Eisav’s sins were forgiven. This is signified in the name Machlas, forgiveness.

Upon reflection, this is incredible! Eisav, an arch-evildoer and murderer, was fully forgiven of all his sins on the day that he got married!

This concept is found in the Gemara as well (Yevamos 63b). The Gemara states: “Rav Chama bar Chanina said, as soon as a man marries a woman his sins are ‘stopped up’.” The word used is מתפקקין, the same word that is used in reference to a cork, or a seal. This is commonly understood to mean that his sins are forgiven and eradicated.

However, the in the Rif’s commentary to the Ein Yaakov he questions the use of this terminology. Wouldn’t it have been easier and more precise to say ‘forgiven’? He explains beautifully – on the day of the chuppah the sins of the groom are stored away and sealed up, but they are not yet forgiven.

In essence, he is being presented with a clear choice. You are now starting a new life, together with your new wife. You, as a couple, have the unique opportunity to start afresh, and to pursue a life of spirituality and mitzvos. However, you also have the option to fall back into your old and comfortable ways, which were possibly sin splattered.

Should you choose to walk a new path, and forge a new life together as a couple of Torah and Mitzvos, then the sins from your premarital state will remain corked and sealed (and will even ultimately be considered meritorious, as is with one who does Teshuvah out of love).

However, should you choose to continue in your old, non-elevated ways, then your sins will be uncorked and will still be considered ‘yours’. Because you haven’t started a new life together, you’ve just continued along the previous path.

The Rif goes on to explain that this is the intent of the next sentence of the Gemara: “In the West (Israel) they would ask a man upon his marriage, מצא או מוצא, was your marriage a fulfillment of the verse “He who finds a wife finds great good” (Mishlei 18:22) or the verse “I find a woman to be more bitter than death” (Koheles 7:26).

They weren’t questioning his state of marital bliss, indeed it was far too early to ascertain if the marriage would be a happy one. Rather they were asking a spiritual question – will you use the opportunity of a fresh start with your new wife to seek good? Or will you trudge along the path that will lead to a certain spiritual death?

It seems that even Eisav was presented with this opportunity, notwithstanding that this was not his first marriage, and he was already well established in his ways of debauchery, even so he was given the opportunity to have a fresh start.

Reb Yisroel of Brunia (a 15th Century scholar) quoted by the Rema (Even Haezer 61:1) records a custom for the bride and groom to fast on the day of their wedding. Since it is a day of forgiveness for them it would be appropriate to fast. [The Torah Temimah adds a nice twist – Eisav married Machlas to please his parents. The good deed together with his marriage effected the opportunity for forgiveness. So too we fast in order to add a righteous act to the marriage and effect forgiveness].

A second reason, given by the Mahari Mintz, for fasting is to ensure that they do not become intoxicated, and have the appropriate serious approach to the chuppah.

One practical difference between the two reasons will depend on the scheduling of the chuppah. If the reason for fasting is for forgiveness it would be like any other fast – dawn to nightfall. Even if the chuppah takes place early in day it would be logical to fast all day. However, according to the second reasoning, that we are merely avoiding frivolity at the chuppah, there is no reason to fast once the chuppah and kidushin are over.

Conversely, if the chuppah is after nightfall, according to the first reasoning, you’ve already fasted the day and there is no longer any reason to fast. However if one is concerned about intoxication they would be required to fast until after the chuppah.

Both reasons are quoted in the meforshim to Shulchan Aruch as well as in the Mishnah Berurah (573:8).

The Aruch Hashulchan understands the second reasoning to be primary, and in all situations rules that one should fast until after the chuppah. However the Chochmas Adam (129:2) writes that since the fast is only a custom, and not cited in the Gemara, one may definitely be lenient when the chuppah is after nightfall and eat before the chuppah, as long as they are careful to avoid any intoxicating beverages.

The custom is to break the fast immediately after the chuppah regardless. The Ezer Mikodesh (quoted in the Torah Ledaas) explains that even if it’s considered a personal Yom Kippur for the bride and groom, after the chuppah is the equivalent of after Neilah, the fast is complete.

One fasts even on Rosh Chodesh or during the month of Nissan and other days that we don’t say tachanun, but not on Chanukah or Purim. (OC 573). The Mishna Berura adds that one does not fast on Isru Chag, the 15th of Av and the 15th of Shvat. The opinion of the Elyah Rabbah is that one never fasts on a day that tachanun is not said.

If one gets married on the day or night following a fast day Rav Moshe Feinstein (OC 1:167) rules that they should fast, and infers by omission that this is the opinion of the Mishna Berura as well. However the Toras Mordechai writes that there is definitely no need to fast on the day following Yom Kippur, and Rav Shlomo Zalman extends this to the day following any fast day.

The Eishel Avraham questions the custom of the Kallah fasting – from the Gemara it seems that only the groom has his sins forgiven? He concludes that she too has her sins forgiven, and therefore should fast as well, however there is more room for leniency with the Kallah than with the Chassan. This is fully understandable according to our initial explanation of the concept – they are both setting out on a new, elevated path together, and therefore it is appropriate for them both to fast.