The Rebbe says:
1. This week’s Torah portion starts off and says that Yehuda (Judah- one of the Twelve Tribes) approached his brother Yosef (Joseph- another one of the Twelve Tribes) to discuss the issue of forcing Binyamin (Benjamin- the youngest of the Twelve Tribes) to remain in Egypt.
The Midrash Rabah tells us that when Yehuda approached Yosef he was ready for anything, even war.
Why did Yehuda take such a firm stance for his brother Binyamin and not any of the other Twelve Tribes? Because Yehuda had promised his father Yakov (Jacob) earlier on that he would be responsible for Binyamin, as the Torah continues this story and quotes Yehuda telling Yoseph, “Because your servant has assumed responsibility for the boy”.