The question naturally arises as to where Reuven had been when Yosef was sold. Bereishit Rabba (84), as cited by Rashi, tells that Reuven had left to pray and weep in his ongoing quest for forgiveness for his sin with Bilha. In this context, the Midrash gives praise to Reuven for his intensive process of repentance, commenting, “The Almighty said to Reuven: Never before had somebody sinned before Me and repented – you are the first to introduce repentance!”
Many writers addressed the question of why the Midrash speaks of Reuven as the first person to sin and repent. According to tradition, Adam underwent a process of sincere repentance after partaking from the forbidden tree, and Kayin repented for murdering his brother. In what sense, then, was Reuven the first sinner to repent?
One answer, perhaps, is that Reuven’s offense, as Chazal understood it, was not as obviously sinful as Adam’s or Kayin’s. Although the Torah (35:22) writes that Reuven slept with Bilha, Chazal understood this account as a euphemistic description of Reuven moving his father’s bed out of Bilha’s tent. After the death of Rachel, Yaakov’s primary wife, Yaakov moved his bed into the tent of Bilha – Rachel’s maidservant whom Yaakov had married years earlier. Reuven saw this as an affront to the honor of his mother, Leah, and so he moved Yaakov’s bed into Leah’s tent. His sin, then, was meddling in his father’s most personal affairs, and the Torah sought to emphasize the gravity of this incident by speaking of Reuven as actually sleeping with his father’s wife. According to this account, Reuven acted with noble motives, out of a desire to defend his mother’s honor. This is quite different from Adam’s clear-cut violation of an explicit divine command, and from Kayin’s act of fratricide. Reuven committed a sin which could be explained and understood, and perhaps even justified.
This, perhaps, is the Midrash’s intent in noting the unprecedented nature of Reuven’s process of repentance. Reuven was the first to repent for a sin that was not obviously sinful, an improper act that at the time seemed warranted. This is a special form of teshuva, because it incorporates not merely remorse and the desire to improve, but also a process of honest self-scrutiny. When we acknowledge committing wrongs which could be and were viewed as legitimate acts, this demonstrates that we are carefully evaluating our conduct with a critical eye. Reuven’s repentance sets for us an important example of introspection and retroactive self-assessment, of the need to study ourselves and our conduct to find mistakes that are camouflaged by a disguise of innocence and noble intentions.