Twelve Tribes No More and No Less and the Blessing Passed From Jacob to Moses

Yalkut Shimoni on Torah 161:5

"All these are the twelve tribes of Israel" (Genesis 49:28) - not fewer and not more. Even Rebekah saw them, as it is said, "And the LORD said to her, Two nations are in your womb" (Genesis 25:23), and so on (as above). "And this is what their father spoke to them; he blessed them." It is not written here "and he blessed them," but rather - why so? Because he gave Judah the strength of a lion, and Joseph the strength of an ox, and Naphtali the swiftness of a deer, and Dan the bite of a serpent. Lest you say that this one is greater than that one, therefore he included them all at the end, as it is said, "each one according to his blessing he blessed them." And because he apportioned the land among them and gave Judah a land that produces barley and Benjamin a land that produces wheat, even so he included these with those. Thus, "And this is what their father spoke to them." It is not written here "this," but "and this he said" - meaning, a man like me will in the future bless you, and from the place where I left off he will bless you, as it is said, "And this is what he spoke to them." And when Moses arose he opened to them with "And this is the blessing" (Deuteronomy 33:1); from the place where their father left off he spoke to them. When do the blessings reach you? From the hour you receive the Torah. Moses said, "From the elders I gain understanding" (Psalms 119:100). When Isaac blessed Jacob, he blessed him with "God Almighty bless you" (Genesis 28:3). With what did he conclude? With a calling: "And Isaac called Jacob and blessed him." And Jacob too began with a calling, "And Jacob called to his sons" (above, verse 1), and concluded with "this is what he spoke." And Moses began to bless in the place where Jacob left off, "And this is the blessing," and concluded with "Happy are you, O Israel; who is like you" (Deuteronomy 33:29). And David opened in the place where Moses left off, as it is said, "Happy" - thus, "From the elders I gain understanding." "I am being gathered to my people" (Genesis 49:29) - he said to them: if you are worthy, you will be joined with me; and if not, when I depart from the world I go gathered to my people. And when he passed away, "his sons did for him as he had commanded them" (Genesis 50:12). "And Jacob finished commanding his sons" (Genesis 49:33) - what did he command them? To carry his bier, three from the east and three from the south and three from the north and three from the west. He said: let none of your sons' sons carry my bier, for among them are some born of the daughters of Canaan, as it is said, "and Saul the son of the Canaanite woman" (Genesis 46:10).

Themes