Genesis 21:28-32

And Abraham set seven ewe lambs of the flock by themselves.

And Abimelech said unto Abraham, What mean these seven ewe lambs which thou hast set by themselves?

And he said, For these seven ewe lambs shalt thou take of my hand, that they may be a witness unto me, that I have digged this well.

Wherefore he called that place Beer-sheba; because there they sware both of them.

Thus they made a covenant at Beer-sheba: then Abimelech rose up, and Phichol the chief captain of his host, and they returned into the land of the Philistines.