After making their covenant at Beersheba, Abimelech left with Phicol, the commander of his army, and they returned home to the land of the Philistines. Then Abraham planted a tamarisk tree at Beersheba, and there he worshiped the Lord, the Eternal God.Genesis 21:33-34
El-Olam: The Everlasting (or Eternal) God
Abraham had his promised son. The Lord had defended Him time and time again, including in this treaty of Beersheba, and granted him favor for his faith. His life was a story about how who matters more than do. His faith was in Yahweh Elohim, Adonai, El Shaddai, El-Olam, the God he knew. The God who, throughout his whole life, never went away, but showed Himself present and active over and over again. The God who lasted though nothing else did; the everlasting God.