Do not be afraid: Abram did not have a son to inherit his property. The Lord addressed Abram’s anxiety about the future with comforting words.
I am your shield: The Hebrew word for shield (magen) comes from the same root word as Melchizedek's word delivered (14:20). The Lord, who had delivered Abram's enemies into his power, would continue to protect him.
your very great reward: The promise of children was still unfulfilled (12:2–3; see also Psalm 127:3).