What does Genesis 20:9 mean?
Abimelech appears to be rightfully angry. He calls Abraham before him and confronts him with very similar questions to those asked of Abraham by an Egyptian Pharaoh many years earlier (Genesis 12:18–19). Here, though, the questions have a more pointed tone. Abraham has lied and told Abimelech that Sarah is his sister, leaving out the full truth that they are actually married. When Abimelech took Sarah into his house as an additional wife, he was stricken with a disease and confronted by God in a dream (Genesis 20:3).Abimelech wants to know what he has ever done to Abraham. It's a question asked by a reasonable person: Did I do something to deserve this terrible treatment from you? Unlike the Pharaoh, Abimelech also identifies this near-adultery as a great sin with consequences for himself and his whole kingdom. He seems to agree with God that adultery is wrong. He says clearly to Abraham: You shouldn't have done this.