In the Midrash, Chazal infer from the word “machlas,” which is a derivative of the word “mochal,” to forgive, that when Eisav took a wife, Hashem forgave his prior sins. Furthermore, Chazal say that when one gets married, all of his sins are forgiven. We must endeavor to understand this. Why should Eisav’s sins be forgiven because he entered into matrimony? Is marriage some kind of magic moment, such that the instant one places a ring on his kallah’s finger, all of his prior transgressions are erased? For the sin of chillul Hashem, even teshuvah, repentance on Yom Kippur is not sufficient penance to wipe the slate clean, but marriage is? How are we to understand this?
Horav Sholom Schwadron, z.l., cites Horav Shlomo Zalmen Auerbach, z.l., who gives a novel explanation. When a person stands at the threshold of a change in status, and he is about to go enter a new position in life, he has within himself a koach ha’hischadshus, power of renewal, to be reinvigorated spiritually and begin anew. The sins of his past, which unfortunately are so much a part of his life, drag him down as it seals off his heart, the seat of his emotions, rendering him impervious to any positive change. At this juncture, Hashem grants him temporary absolution from the weight of his sins. They are put aside for one day to see what he will do. If he avails himself of this opportunity, if he decides to turn his life around, to repent and accept upon himself a life of virtue and service to Hashem, he has entered this new stage, pure and free of sin. If he allows this window of opportunity to go to waste, then as soon as his nuptials are over, he is back where he started. Apparently, Eisav chose the latter approach.