There is a certain irony to the dramatic confrontation between Yosef and his brother Yehudah at the beginning of this week's Parsha. The regal Yosef, acting in his capacity as second in command of all Egypt, is listening to Yehudah plead on behalf of Binyamin. Yet the true royal personage in the palace is Yehudah, not Yosef. It is Yehudah, when all is said and done, who receives the מלוכה, the privilege and responsibility to rule over Bnai Yisrael. Yehudah's name is even used eventually to identify us as a people; we are called יהודים, Jews, as noted by the Midrash in Bereishis Rabbah (פרשה צ"ח סימן ו').
Rav Ahron Soloveichik offers us insight into the selection of Yehudah to receive the מלוכה instead of Yosef. The Rambam, in his introduction to Pirkei Avos )שמונה פרקים פרק ו'( discusses two character types: the חסיד מעולה, the person whose spirituality and saintliness is inherent, and the מושל בנפשו, the one who is able to curb and redirect his natural tendency to sin and to transform it so as to attain perfection. The Rambam shows that in Judaism, the latter person, the מושל בנפשו, is generally considered by Chazal to be the superior person.
Yaakov described his son Yosef as a חסיד מעולה -gifted by Hashem at birth with an inner desire to do good, saying that Yosef was gifted with "blessings of heaven above, blessings of the deep that lies below, blessings of breasts and womb" (בראשית מ"ט: כ"ג). True, and to his great credit, Yosef experienced, and overcame, many external struggles (such as with Potiphar's wife), but there was an inner purity to him which made it all possible.
In contrast, Yehudah's strength comes from Teshuvah, repentance. When he admitted צדקה ממני"," that Tamar was more righteous than he (שם ל"ח: כ"ו), his process of Teshuvah began. When Yehudah admitted his error, he started on the road to becoming a מושל בנפשו. In his Beracha to Yehudah, Yaakov says, "Yehudah is a lion's whelp, from the prey, my son, you have elevated yourself; he stooped down and crouched as a lion, and as a lioness, who shall raise him up" (שם מ"ט: ט'). In the words of Rav Ahron, "Originally, Yehudah was a lion's whelp, impelled by various drives, but he elevated himself from his prey. After selling Yosef, Yehudah, the lion, which is the symbol of freedom, was willing to subordinate himself and surrender his freedom to save Binyamin."
In order to be a proper ruler, a king must understand the heart and mind of his people. Any person, with effort, can be a מושל בנפשו, while there are few who can be described as a חסיד מעולה. Therefore, Yehudah, the מושל בנפשו, was most fit to rule over Bnai Yisrael.
Insight into calling Bnai Yisrael "יהודים" can be gained by studying Yehudah's plea for Binyamin. Yehudah brought out two points -- the anguish of Yaakov were Binyamin not to return, and the fact that Yehudah had guaranteed Binyamin's safety. Logically, the legal argument should have been presented first, followed by an appeal to Yosef's compassion, to avoid causing Yaakov anguish. However, in Judaism, the moral obligation to go beyond the letter of the law to its spirit takes precedence over a purely legalistic approach. Yehudah had his priorities right; we, as יהודים, must do no less.