God promised that Abraham would have many descendants, and that the nation descended from him would possess the land of Canaan. God also promised that through one of Abraham's descendants, the whole world would receive blessing.
See Genesis chapter 17 and also Genesis 22:15-18 for the Bible's account of these covenant promises.
The covenant that God made with Abraham was a unilateral (one-sided) promise from God to Abraham. Apart from anything Abraham did, God was promising that he was going to bring about a great nation from Abraham's offspring, and that the Messiah (meaning "The Anointed One") would come from Abraham's descendants, as one through whom the whole world would receive favor from God. As God promised Abraham, "Through your offspring all nations on earth will be blessed" (Genesis 22:18).
