"…From the prey, my son [Judah], you withdrew…." (Gen. 49:9)
Rashi: "Withdrew and said, "What is the gain [if we slay our brother and cover up his blood]?" (Gen. 37:26)
[Judah withdrew] from killing Tamar, when he confessed, "She is right, [it is] from me…" [even though doing so entailed publicly repenting and thereby shaming yourself.] (Gen. 38:26)

Reuben's intentions in saving Joseph seem nobler than Judah's: Reuben wanted to save Joseph and bring him back to his father; Judah saved Joseph only so that he could be sold into slavery.

Similarly, Reuben's repentance over Joseph seems far superior to Judah's concerning Tamar. Firstly, Judah simply admitted that he was guilty, whereas Reuben repented through fasting and other forms of penitence for many years. Secondly, Judah knew that if he did not admit his guilt, three lives would have been taken unjustly; no comparable consequence compelled Reuben to repent.

...the primary function of the king and the priest is to serve others.

Nonetheless, Judah's deeds actually helped people, whereas Reuben's did not. (In fact, had Reuben not been preoccupied with his personal repentance, he might have been able to save Joseph.) Therefore, Reuben lost the kingship to Judah and the priesthood to Levi, for the primary function of the king and the priest is to serve others.

This teaches us that we cannot be satisfied with devoting ourselves only to our own spiritual perfection; we must also engage in helping others.

Furthermore, the difference between self-involvement and care for others can spell the difference between exile and redemption: Reuben's preoccupation with his own spiritual state indirectly contributed to Joseph's sale to Egypt and the eventual exile in Egypt, the precursor of all future exiles. Judah's repentance, in contrast, may not have been as profound as Reuben's, but it saved three lives, one of which was the ancestor of the Messiah, who will end all exile.

Adapted from Likutei Sichot, vol. 15, pp. 442-446
© 2001 Chabad of California/www.LAchumash.org