In the year 15 of Abraham's dwelling in the land, 70 years of Abraham's life [(that was the year 2018 after the Garden of Eden)], Hashem appeared to Abraham and said to him: "I am Hashem who brought you out of Ur Kasdim," etc. "And you shall come to your fathers in peace, and the fourth generation shall return here," etc. And he built an altar, etc. [(Sefer HaYashar)].