Moses
Genesis 21:32BSB·traditional attribution

After they had made the covenant at Beersheba, Abimelech and Phicol the commander of his army got up and returned to the land of the Philistines.

Matthew Henry Presbyterian @wholebiblehenry

We have here an account of the treaty between Abimelech and Abraham, in which appears the accomplishment of that promise (Gen 12:2) that God would make his name great. His friendship is valued, is courted, though a stranger, though a tenant at will to the Canaanites and Perizzites. I. The league is proposed by Abimelech, and Phichol his prime-minister of state and general of his army. 1.

Commenting on Genesis 21:22-32

Jamieson-Fausset-Brown Reformed @jfbcommentary

COVENANT. (Gen 21:22-34) Abimelech and Phichol--Here a proof of the promise (Gen 12:2) being fulfilled, in a native prince wishing to form a solemn league with Abraham. The proposal was reasonable, and agreed to [Gen 21:24].

Commenting on Genesis 21:22-34

Geneva Bible Notes Reformed @genevanotes

Thus they made a covenant at Beersheba: then Abimelech rose up, and Phichol the chief captain of his host, and they returned into the land of the Philistines. (m) Thus we see that the godly, concerning outward things may make peace with the wicked that do not know the true God.