As we discussed yesterday, Reuven, as told in Parashat Vayeshev, attempts to save the life of his brother Yosef, whom the other brothers had decided to kill. Reuven recommends to his brothers that they cast Yosef into a pit rather than kill him, with the intention that he, unbeknownst to his brothers, would later rescue Yosef. However, after Yosef is cast into the pit, Yehuda instructs his brothers to sell Yosef as a slave. When Reuven, who was apparently absent when Yehuda made his suggestion, returns to the pit to rescue Yosef, he is astonished to discover that Yosef is gone.
Where had Reuven gone, that he did not hear Yehuda's recommendation to his brothers? Rashi (37:29) cites one view from the Midrash that Reuven left to occupy himself in prayer and repentance over his sin of bringing Yaakov's bed out of Bilha's tent and into Leah's tent, a grave infringement on his father's honor (see 35:22 and Rashi).
(Rashbam explains this entire episode differently, claiming that the brothers sat at a distance from the pit and were unaware that Yosef was lifted from the pit by Midyanite merchants. Reuven never left his brothers, but rather returned to the pit upon hearing their plan to sell Yosef, to save him, only to discover that he was gone.)
What connection did Chazal see between the sale of Yosef and Reuven's sin of moving his father's bed? Why suddenly now does Reuven involve himself in repentance for this transgression?
Rav Soloveitchik is cited (by Rav Michael Shurkin, in his "Meged Giv'ot Olam") as offering the following explanation. Several Midrashim portray the ten brothers' decision to kill Yosef as a formal judicial ruling. They convened as a Bet-Din and reached the conclusion that Yosef was deserving of this punishment for having slandered them. Why, then, should they be criticized for their mistreatment of Yosef? If, indeed, they rendered an official ruling as a rabbinical court, then even if they were mistaken, they should not be punished for their error.
The answer, Rav Soloveitchik claimed, is clear: they did not consult on the matter with their father. Their hostility toward Yosef and objection to Yaakov's preferential treatment of him displayed an utter disregard for their father's judgment. They never even consulted with Yaakov on this matter, for they concluded on their own that he was in error and Yosef deserved to die. What allowed the sale of Yosef to occur was an attitude of disrespect towards Yaakov.
We can now understand the connection between Reuven's wrongdoing and the sale of Yosef. Reuven's infringement on his father's honor showed his brothers that decisions can be made without consulting a higher authority, that they are now independent of Yaakov and need not confer with him issues of major import. Upon seeing where this exaggerated sense of autonomy led, Reuven resumed his "fasting and sackcloth" over his transgression. He understood that his act had set a dangerous precedent for his younger brothers, who now considered themselves capable of independently deciding on matters of life and death without consultation with their father.