Sifrei Devarim 312

¹(Devarim 32:9) "For the portion of the L-rd is His people": An analogy: A king had a field and gave it to tenant-farmers, who began to steal from it — upon which he gave it to their sons — who began to be worse than the first. When a son was born to him, he said to them: Get out of what is mine. You cannot remain there. Give me my portion so that I can recognize it. Similarly, when our father Abraham came to the world, there issued from him base matter — Ishmael and the sons of Keturah. When our father Isaac came to the world, there issued from him base matter — Esav and the chiefs of Edom, who became worse than the first. When Jacob came, no base matter issued from him, but all of his sons were born kasher , as he was, as it is written (Bereishit 25:27) "And Jacob was a whole (i.e., "unalloyed") man, a dweller of tents" (the tents of Torah). From where does the L-rd recognize His portion? From Yaakov, as it is written (Psalms 135:4) "For Yaakov did G-d choose; Israel, as His select ones," and (Devarim, Ibid .) "For the portion of the L-rd is His people, Jacob the cord of His inheritance." And we still do not know whether the L-rd chose Israel as His inheritance, or Israel chose the L-rd, (both readings being possible). It is, therefore, written ( Ibid . 7:6) "You (Israel) has the L-rd your G-d chosen to be unto Him a select people." And whence do we derive that Jacob, likewise, chose the Holy One Blessed be He? From (Jeremiah 10:16) "Not as those is the portion of Jacob, for He is the Former of all, and Israel is the tribe of His inheritance; the L-rd of hosts is His name." ²"Jacob is the chevel of His inheritance": " chevel " is a lot, as it is written (Psalms 16:5) " chavalim have fallen to me in pleasant places," and (Joshua 17:5) "And the lots of Menasheh fell — ten." ( Ibid . 19:9) "From the chevel of the children of Judah was the inheritance of the children of Shimon": Just as a chevel (a rope) is three-fold, so Jacob was the third of the fathers, and he received reward over and against all of them. When Abraham was born, what is written? (Proverbs 17:17) "And a brother (Abraham) is born for affliction" (see beginning of # 311). When Israel was born, what is written? (Koheleth 4:9) "Better the two than the one." When Jacob was born, what is written ( Ibid . 4:12) "And the three-fold cord is not soon sundered."