God called Abraham to leave his home and promised to make him a great nation, give him many descendants, and bless all people through him. Abraham obeyed God and had faith in his promises, even though having a child seemed impossible. God tested Abraham's faith by commanding him to sacrifice his son Isaac, and Abraham was willing to obey until an angel stopped him. God provided a ram for the sacrifice instead of Isaac, fulfilling his promise to make Abraham's descendants as numerous as the stars.