What were the failures of Abraham the patriarch?

Answer 1

Abraham lied about the relationship of himself and his wife Sarah, telling the kings of Egypt and of Gerar that she was his sister.

Abraham also went along with Sarah's lack of trust in God's promise of a son when he fathered Ishmael through Hagar, Sarah's handmaiden.

• Answer 2

Abraham had no failures.

1. He called Sarah his sister in order to save his life (Genesis ch.12 and ch.20) as stated explicitly in the text. Surely that is no sin.
2. He took Hagar in order to bear a son, because God had promised that he would have children (Genesis 12, 13 and 15), but had never said that Sarah would have a child. God promised Sarah a son only years after Hagar had had Ishmael (Genesis 16-17).