Albert Barnes Commentary 1 Kings 20:1

"And Ben-hadad the king of Syria gathered all his host together; and there were thirty and two kings with him, and horses and chariots: and he went up and besieged Samaria, and fought against it." — 1 Kings 20:1 (ASV)

Ben-hadad, the king of Syria - This was probably the son of the Ben-hadad who assisted Asa against Baasha (1 Kings 15:18).

Thirty-two kings with him - These were not allies, but subordinate rulers (1 Kings 20:24). During the reign of this Ben-hadad, Damascus had become the center of a significant monarchy, which likely extended from the Euphrates to the northern border of Israel. The Assyrian inscriptions show that around this time, the region was divided into numerous small kingdoms, with the primary tribes being the Hittites, the Hamathites, and the Syrians of Damascus.

Horses and chariots - The Assyrian inscriptions show how vital the chariot force was considered as a branch of the military by the Syrians. A king, who has been identified with this Ben-hadad, brought nearly four thousand chariots into the field against Assyria.