James 2:22

You see that (his) faith was working together with his works, and as a result of the works, his faith was completed (reaching its maturity when he expressed his faith through obedience).

Because Abraham believed God’s promises, he acted on that belief. When we believe in the Word of God, we must act on our faith. No matter how small it may seem, the action is a movement of faith. If we don’t believe something is possible, we will take no action.