Saul said, There shall not a man be put to death this day; for today Yahweh has worked deliverance in Israel.
Just really decimated the troops. And God gave unto Saul a great victory. It really was the thing that sort of catapulted him into the real position of king. This is what the people were looking for, a man who would go out and lead their armies into battle against their enemies and all. So when this great victory was given to Saul over their enemies, then