What promise did the Israelites believe God made to Abraham?

Genesis 17:2--5 And I will make my covenant between me and thee, and will multiply thee exceedingly. 3. And Abram fell on his face: and God talked with him, saying, 4. As for me, behold, my covenant is with thee, and thou shalt be a father of many nations. 5. Neither shall thy name any more be called Abram, but thy name shall be Abraham; for a father of many nations have I made thee.