And it shall be, when thou shalt hear a sound of going in the tops of the mulberry trees, that then thou shalt go out to battle: for God is gone forth before thee to smite the host of the Philistines.

So David received them and assigned them to be officers over troops. Some of the descendants of Manasseh joined David when he was going to fight against Saul, accompanied by the Philistines. Even so, David was of no help to them, because the Philistine rulers were counseled to send him away. They told themselves, "He's going to go over to his master Saul at the cost of our heads."

Then David asked of God, saying, Shall I go up against the Philistines? and wilt thou deliver them into my hand? And Yahweh said to him, Go up, and I will deliver them into thy hand.

And the Philistines heard that David was anointed king over all Israel, and all the Philistines went up to seek David; and David heard of it, and went out against them.