2 Samuel 5:17-19

When the Philistines heard that David had been anointed king over Israel, all the Philistines went up to look for him, but he heard about it and went down to the stronghold. Now the Philistines had come and spread out [for battle] in the Valley of Rephaim. David inquired of the LORD, saying, “Shall I go up against the Philistines? Will You hand them over to me?” And the LORD said to David, “Go up, for I will certainly hand them over to you.”