Eighteen Mentions of the Patriarchs and the Eighteen Blessings

"And He said: I am the LORD, the God of Abraham your father and the God of Isaac" (Genesis 28:13). Eighteen times the Torah mentions the patriarchs together, and corresponding to this the Sages fixed eighteen blessings in the Amidah prayer. And if a person says to you, "They are nineteen," say to him: "And behold, the LORD stood over him" — that one is not counted among them. And if a person says to you, "They are seventeen," say to him: "and let my name be called upon them, and the name of my fathers Abraham and Isaac" (Genesis 48:16) — that one is one of them. Rabbi Shmuel bar Nachmani said: corresponding to the eighteen commands that are written in the second account of the Tabernacle, from "and with him Oholiab" (Exodus 38:23) until the end of the book. "The land on which you lie" (Genesis 28:13). Reish Lakish in the name of Bar Kappara said: He folded it like a writing tablet and placed it under his head, like a person who says, "What is under your head is yours." Rabbi Huna in the name of Rabbi Elazar said: this was only on condition that he would be buried upon it.