In advance of his arrival in Egypt, Jacob sent Judah to prepare a yeshiva – a place where he and his descendants could devote themselves to constant study of the Torah.
Undistracted Attention to Spiritual Growth
וְאֶת יְהוּדָה שָׁלַח לְפָנָיו אֶל יוֹסֵף לְהוֹרֹת לְפָנָיו גֹּשְׁנָה וגו': (בראשית מו:כח)
[Jacob] sent Judah ahead of him to Joseph, to make advance preparations in Goshen. Genesis 46:28
Jacob sent Judah to start a school rather than asking Joseph to do so, recognizing that a Torah academy must be headed by a person who is completely removed from mundane affairs and is fully immersed in the study of the Torah. Since Joseph’s Divine mission required that he run the mundane affairs of Egypt, he could not also head Jacob’s school of Torah, notwithstanding his undisputed righteousness.

Likewise, those who wish to adopt the vocation of the Torah scholar or teacher must be both allowed and required to be completely separated from worldly affairs, in order to be able to focus on educating our children without any distractions.1

FOOTNOTES
1. Likutei Sichot, vol. 3, pp. 827–830. See Eiruvin 65a.