After these things the word of the Lord came unto Abram in a vision, saying, Fear not, Abram: I am thy shield, and thy exceeding great reward. (Genesis 15:1, KJV)
Abraham was human just like us. When we have moments of unbelief, God would remind us of His Word and promise so that we would be encourage and confident in doing His will. When you read the scriptures of Abraham’s journeys, it seems as though he has gotten away with lying about his wife being his sister. When Abraham entered into Egypt after building an alter between Bethel and Hai and calling on the name of the Lord, he had a moment of unbelief. He was afraid for his life. His wife was a very attractive woman. Abraham thought to be killed by the Egyptians for his wife to be taken. But God protected him and his wife and provided them with riches from Egypt after they return back to Bethel in Canaan, the land where there was a grievous famine, the same land that God promised Abraham. In spite of Abraham’s moment of unbelief, God sent His Word to increase his faith.
After God increased Abraham’s faith, he had another unbelief moment in Gerar. Abraham repeated the same lie of saying that Sarah is his sister to protect himself and his wife. Abraham’s faith was not yet perfect, but God in His wisdom gave Abraham the faith that was needed to do His will. God has provided us with a gift of righteousness through faith and not works because sin and unbelief will always be with us until God perfects us. Therefore, we are responsible for keeping our heart and motive in the right place in order for God to work with us in our walk with Him.