Genesis 21:22-31

Then Abimelech came with Phicol, the commander of his army, and said to Abraham, “God is with you in everything you do. So make a promise to me here before God that you will be fair with me and my children and my descendants. Be kind to me and to this land where you have lived as a stranger—as kind as I have been to you.” And Abraham said, “I promise.” Then Abraham complained to Abimelech about Abimelech’s servants who had seized a well of water. But Abimelech said, “I don’t know who did this. You never told me about this before today.” Then Abraham gave Abimelech some sheep and cattle, and they made an agreement. Abraham also put seven female lambs in front of Abimelech. Abimelech asked Abraham, “Why did you put these seven female lambs by themselves?” Abraham answered, “Accept these lambs from me to prove that you believe I dug this well.” So that place was called Beersheba because they made a promise to each other there.