What is "Es Tuv Eretz Mitzrayim"?
Rashi #1: It refers to Eretz Goshen.
Rashi #2: Par?oh unwittingly prophesied 1 that when Yisrael would leave Egypt, they would take all the wealth of Egypt with them, leaving it [empty] like the depths of the sea - where there are no fish. 2
Ha'amek Davar: Par?oh meant that he would appoint Ya?akov to work for him in the best part of Egypt.
Targum Yonasan: It is referring to the most precious part of Egypt. 3
Riva: He meant to say ?Eretz Goshen?, but mistakenly said "Eretz Mitzrayim"
Gur Aryeh: Fish are not found in the deep ocean (only in shallow waters). When Yisrael left Egypt, they made it as empty as deep waters - which contain no fish.
Perhaps he is referring to Eretz Goshen. See also Na?ar Yonasan.
Why does it say "u'Vo'u Elai"?
Malbim: Yosef has authority to tell his brothers to come to him, but not to come to Egypt to settle; refer to 45:19:1:5.
Ha'amek Davar: You will remain in Egypt under my jurisdiction and service.
