Genesis 21:23-31

23Now therefore swear to me here by God that you will not deal falsely with me or with my descendants or with my posterity, but as I have dealt kindly with you, so you will deal with me and with the land where you have sojourned.” 24And Abraham said, “I will swear.” 25When Abraham reproved Abimelech about a well of water that Abimelech’s servants had seized, 26Abimelech said, “I do not know who has done this thing; you did not tell me, and I have not heard of it until today.” 27So Abraham took sheep and oxen and gave them to Abimelech, and the two men made a covenant. 28Abraham set seven ewe lambs of the flock apart. 29And Abimelech said to Abraham, “What is the meaning of these seven ewe lambs that you have set apart?” 30He said, “These seven ewe lambs you will take from my hand, that this may be a witness for me that I dug this well.” 31Therefore that place was called Beersheba, because there both of them swore an oath.