Genesis 21:32-34

So they made a covenant at Beersheba; and Abimelech and Phicol, the commander of his army, arose and returned to the land of the Philistines. Abraham planted a tamarisk tree at Beersheba, and there he called on the name of the LORD, the Everlasting God. And Abraham sojourned in the land of the Philistines for many days.