What does Genesis 20:3 mean?
As He often does in the Bible, God appears to someone in a nighttime dream. God very matter-of-factly tells Abimelech, king of Gerar, that he is a dead man. He is guilty of adultery because Sarah is another man's wife. Abimelech had apparently been quite ill—a disease sent by God specifically as a warning about the situation with Sarah (Genesis 20:17). Later verses also indicate that all of the women in Abimelech's household were afflicted with barrenness, for the same reason (Genesis 20:18).As the following verses will reveal, even the pagan Abimelech understood adultery to be a great sin. Abimelech will defend himself to God based on two main claims: that he had not actually yet slept with Sarah, and that he did not know she was married (Genesis 20:4–5). After God reassures him that the situation can be resolved, Abimelech will scold Abraham for his lie, demanding an explanation for why such a thing was done (Genesis 20:9).