Has someone persuaded you that Israel was only an unsophisticated, barely functioning gathering of various tribes? When you read the Old Testament, you should see the sophistication of Israel. Consider the organization of the army during the days of David,

And the children of Israel, according to their number, the heads of fathers’ houses, the captains of thousands and hundreds and their officers, served the king in every matter of the military divisions. These divisions came in and went out month by month throughout all the months of the year, each division having twenty-four thousand (1 Chronicles 27:1).

Then the writer showed the breakdown of the divisions. Yes, Israel during David’s reign won every battle, and yes, it was because the Lord was with David and Israel, but that did not preclude David and Israel from doing what they had to do to be successful, even as David knew how to sling stones when he killed Goliath, although the Lord was with David.