and that all this assembly may know that Yahweh doesn't save with sword and spear: for the battle is Yahweh's, and he will give you into our hand.
and he will give you into our hands; not only this Philistine into the hands of David, but the army of them into the hands of the Israelites; David knew, and was assured of this by the Lord, and it was on this he relied, and was what animated him to engage with this champion in the manner he did.