God said: You sold [Joseph] the son of Rachel for 20 meah which equals five selaim; therefore, in every generation, each of you will redeem you firstborn for five selaim. Alternatively, God said to the tribes " You sold the son of Rachel... as such, each of you will bring a half shekel".
Just as four kings are referenced in this episode, we will eventually have four more kingdoms: Babylonia, Media, Greece, and Edom (Rome).
(28) Isaac favored Esau because he "trapped with his mouth"; but Rebekah favored Jacob.
(1)[THERE WAS HUNTING] IN HIS MOUTH — Understand this as the Targum renders it: in Isaac’s mouth (i. e. Isaac ate the venison he brought home). But its Midrashic explanation is: there was hunting in Esau’s mouth, meaning that he used to entrap and deceive him by his words (Genesis Rabbah 63:10).
(1) THE THRESHING FLOOR OF ATAD — It was so called became it was surrounded by a hedge of thorns (not because thorns were threshed there) Our Rabbis explained that it was so called in consequence of an incident that occurred there — that all the kings of Canaan and the princes of Ishmael came to wage war against them, but as soon as they saw Joseph’s crown hanging over Jacob’s coffin they all rose and hung their crowns on it and thus wreathed it with crowns like a threshing floor that is surrounded with a hedge of thorns (Sotah 13a).
(2) The LORD was with Joseph, and he was a successful man; and he stayed in the house of his Egyptian master. (3) And when his master saw that the LORD was with him and that the LORD lent success to everything he undertook, (4) he took a liking to Joseph. He made him his personal attendant and put him in charge of his household, placing in his hands all that he owned.
(1) THAT THE LORD WAS WITH HIM — the name of God was a familiar word in his mouth (Midrash Tanchuma, Vayeshev 8).