Abraham is a wonderful example of living and obeying by faith. He made significant mistakes, but he learned from these experiences, and God used him to teach the people who have read of his life since then what it means to follow God's leading.
"As Abraham and other holy men of old were a light in their generation, so must God’s people be a light in the world. The beams of heaven’s attractive loveliness are to shine forth from us, showing the only good and right way, and ever showing the superiority of God’s law above every human enactment. Bible religion is not to be hidden away in the dark. It delights to be examined. Every additional ray of light that shines upon our pathway is, in God’s plan, a fresh element of strength, an added power by which to draw the world to God." (Read all of this instructive article on Abraham's life.)
"God estimated Abraham’s obedience and unswerving faith, and gave him the name of “Father of the faithful.” The example of Abraham is recorded in sacred history for the benefit of his believing children. This great act of faith teaches the lesson of implicit confidence in God, perfect obedience to his requirements, and a complete surrender to the divine will. In the example of Abraham we are taught that nothing we possess is [too] precious to give to God." (Read all of this wonderful sermon on Abraham's faith in being willing to sacrifice Isaac.)