Charles Spurgeon Commentary 1 Kings 20:27-28

"And the children of Israel were mustered, and were victualled, and went against them: and the children of Israel encamped before them like two little flocks of kids; but the Syrians filled the country. And a man of God came near and spake unto the king of Israel, and said, Thus saith Jehovah, Because the Syrians have said, Jehovah is a god of the hills, but he is not a god of the valleys; therefore will I deliver all this great multitude into thy hand, and ye shall know that I am Jehovah." — 1 Kings 20:27-28 (ASV)

But the Syrians filled the country. And there came a man of God, and spoke to the king of Israel, and said, Thus says the LORD, Because the Syrians have said, The LORD is God of the hills, but he is not God of the valleys, therefore will I deliver all this great multitude into your hand, and you shall know that I am the LORD.

See how good came to Israel through the blasphemy of the Syrians! Whenever a particularly bad book is brought out against the religion of Jesus Christ, or an especially villainous blasphemy is invented against the grace of God, you may almost clap your hands and say, "Now will God rouse himself for his truth and for righteousness's sake. These men will provoke him so that he will arise and defend his own cause."