Abraham said of his wife Sarah, “She is my sister.” Then Abimelek king of Gerar sent for Sarah and took her.
Abraham says that Sarah is his sister for the second time, but despite this lack of faith, God intervenes. The situation could end with Abraham running for his life but, instead, it ends with Abraham praying for Abimalek and receiving his wife back, untouched.
Abraham fears man more than God. God blesses. Abraham sins. God blesses. Abraham does not learn from his previous mistakes. God blesses. I can't out-sin God's blessing. Yes, sin has consequences (look at the cross), but God is gracious despite my sin, not because I've managed to do it a bit less.