Genesis 21:25-31

Then Abraham complained to Abimelech about a well that Abimelech’s servants had taken by force from Abraham’s servants. “This is the first I’ve heard of it,” Abimelech answered. “I have no idea who is responsible. You have never complained about this before.” Abraham then gave some of his sheep, goats, and cattle to Abimelech, and they made a treaty. But Abraham also took seven additional female lambs and set them off by themselves. Abimelech asked, “Why have you set these seven apart from the others?” Abraham replied, “Please accept these seven lambs to show your agreement that I dug this well.” Then he named the place Beersheba (which means “well of the oath”), because that was where they had sworn the oath.