The Bible records several promises of God. Important examples include his promise to Noah to never again destroy humankind by a flood, his promise to send a savior after the fall of Adam and Eve and his promise to Abraham that he would make his descendants numerous like the stars.
Genesis 9 records that God, after having spared Noah, his family and representatives of the animal kingdom from the worldwide flood, made a covenant with the survivors in which he promised to never again destroy the world by a flood. The Bible mentions that God put a rainbow in the sky, which was to be the sign of his promise.
Genesis 3 tells of the fall of Adam and Eve from immortality to a life of sin and death. Both had fallen to the temptations of the devil, who, under the guise of a serpent, convinced the couple to disobey God. In response, God not only assigned punishments to each of the three culprits, but also promised that the woman's seed would conquer the devil. Many Christians see this as a prophecy of the coming of Jesus.
In Genesis 15, Abraham worries that he will die without children, but God promises him that he will make a great people of him, which many believe to be the Jewish people.