Genesis 21:31-34

Wherefore he called that place Beer-sheba; because there they sware both of them. So they made a covenant at Beer-sheba: and Abimelech rose up, and Phicol the captain of his host, and they returned into the land of the Philistines. And Abraham planted a tamarisk tree in Beer-sheba, and called there on the name of Jehovah, the Everlasting God. And Abraham sojourned in the land of the Philistines many days.