While Isaac was living in Gerar, he, like his father Abraham, told people that his wife was his sister. Some think this story repeats the accounts of Abraham’s deception (12:10–20; 20:1–18). But there are more differences than similarities. It is not surprising that a son repeated his father’s lie.
Genesis 26 shows, through many similar patterns, that God’s plan continued through Isaac. Even when Isaac put the covenant at risk, as Abraham had done, God prevented something terrible from happening and protected the marriage. God would bless Abraham’s descendants because of Abraham, but they still needed to trust God themselves to experience those blessings.
True faith in God's promises leads to a life without fear as one follows him. Fear, however, can put the blessing at risk and make a person’s faith seem empty.