1 Kings 20:23

Overview - 1 Kings 20
Ben-hadad, not content with Ahab's homage, besieges Samaria.
13 By the direction of a prophet, the Syrians are slain.
22 As the prophet forewarned Ahab, the Syrians, trusting in the valleys, come against him in Aphek.
28 By the word of the prophet, and God's judgment, the Syrians are smitten again.
31 The Syrians submitting themselves, Ahab sends Ben-hadad away with a covenant.
35 The prophet, under the parable of a prisoner, making Ahab judge himself, denounces God's judgment against him.
Treasury of Scripture Knowledge

1 Kings 20:23  (King James Version)
And the servants of the king of Syria said unto him, Their gods are gods of the hills; therefore they were stronger than we; but let us fight against them in the plain, and surely we shall be stronger than they.

Their gods
It was the general belief in the heathen world, that each district had its tutelary and protecting deity, who could do nothing out of his own province.
28 ; 14:23 1 Samuel 4:8 ; 2 Kings 19:12 ; 2 Chronicles 32:13-19 ; Psalms 50:21 Psalms 50:22 ; Psalms 121:1 Psalms 121:2
Isaiah 42:8