What does Genesis 21:24 mean?

Abimelech, king of Gerar, has asked Abraham to swear to a several things as a way of formalizing an agreement between them. Abimelech had previously given to Abraham the land upon which he and his household were now living. He had seen that Abraham's God is with him in everything. This would have included the miraculous birth of Abraham's son, Isaac, through his wife, Sarah.

Abimelech asked, in essence, that Abraham would swear not to deceive him or his descendants. This provision is made because of the lie Abraham told earlier about Sarah, which nearly cost Abimelech his life (Genesis 20:3–11). Abraham is also asked to swear to act kindly toward Abimelech and the land, in this case meaning the kingdom. Abimelech seems to want to be included in, or least associated with, the blessings Abraham has obtained from God.

Now Abraham replies with what seems to be a short, blunt reply. As the next verse will reveal, Abraham has a complaint he wants to address with Abimelech.