When this was reported to David, he gathered all Israel, crossed the Jordan, and went to Helam. Then the Arameans arrayed themselves against David and fought against him.

2 Samuel 10:16
Hadadezer sent messengers to bring more Arameans from beyond the Euphrates, and they came to Helam with Shobach the commander of Hadadezer's army leading them.

2 Samuel 10:18
But the Arameans fled before Israel, and David killed seven hundred charioteers and forty thousand foot soldiers. He also struck down Shobach the commander of their army, who died there.

And when it was told David, he gathered all Israel together, and passed over Jordan, and came to Helam. And the Syrians set themselves in array against David, and fought with him.