G-d tells Abram that he will have countless descendants

• The Lord came to Abram in a vision, saying, "Fear not, Abram; I am your Shield; your reward is exceedingly great." Abram replied that he has no children and everything would be inherited by his household keeper.
• G-d said: "This one will not inherit you, but the one who will spring from your innards-he will inherit you." And He took him outside, and He said, "Please look heavenward and count the stars, if you are able to count them." And He said to him, "So will be your seed."
• And he believed in the Lord, and He accounted it to him as righteousness.

G-d sets a covenant with Abram, promising his descendants the land from Nile to Euphrates

• And G-d said: "I am the Lord, Who brought you forth from Ur of the Chaldees, to give you this land to inherit it." Abram asked, "O Lord G-d, how will I know that I will inherit it?" G-d told him to make an offering (3 heifers, 3 goats, 3 rams, a turtle dove and a young bird) and Abram did so.
• When the sun was ready to set, a deep sleep fell upon Abram, and behold, a fright, a great darkness was falling upon him. And He said to Abram, "You shall surely know that your seed will be strangers in a land that is not theirs, and they will enslave them and oppress them, for four hundred years. And also the nation that they will serve will I judge, and afterwards they will go forth with great possessions. But you will come to your forefathers in peace; you will be buried in a good old age. And the fourth generation will return here, for the iniquity of the Amorites will not be complete until then."
• Now it came to pass that the sun had set, and it was dark, and behold, a smoking furnace and a fire brand, which passed between these parts. On that day, the Lord formed a covenant with Abram, saying, "To your seed I have given this land, from the river of Egypt until the great river, the Euphrates river. The Kenites, the Kenizzites, and the Kadmonites, And the Hittites and the Perizzites and the Rephaim, And the Amorites and the Canaanites and the Girgashites and the Jebusites."

• that your seed will be strangers From the time that Isaac was born until the Israelites left Egypt was four hundred years. Isaac was 60 years old when Jacob was born, and Jacob, when he went down to Egypt, said,“The days of the years of my sojournings are 130 years,” They were in Egypt 210 years. Total = 400 years. Now, if you should say that they were 400 years in Egypt, this is not so because Kehath was one of those who descended to Egypt. If you compute the years of Kehath (133) and those of Amram (his son, 137), and the 80 years of Moses, his age when they left Egypt, you will find only 350 years. And you must still subtract from them all the years that Kehath lived after the birth of Amram and that Amram lived after the birth of Moses. [from Seder Olam ch. 3]
• for the iniquity of the Amorites will not be complete that they should be sent out of their land until that time, for the Holy One, blessed be He, does not punish a nation until its measure is full, as it is said: (Isa. 27:8):“When her measure is full, when You send her away, then You will strive with her.” - [from Zohar, vol. 1, p. 113b]
• The Kenites There are ten nations enumerated here, but He gave them only seven nations. The other three are Edom, Moab, and Ammon, here referred to as the Kenites, Kenizzites, and Kadmonites, which are destined to be our heritage in the future, as it is said (Isa. 11:14): “upon Edom and Moab shall they stretch forth their hand, and the children of Ammon shall obey them.” - [from Gen. Rabbah 44:23]
• The Rephaim the land of Og (Deut. 3: 13)