Saul was a man who walked by sight and not by faith. Having learnt that David was in the town of Keilah, he assumed that David intended to remain there since it was a fortified town (with gates and bars). This would have given Saul a chance to trap David and he assumed that it was God’s will. He was deluded in thinking that these circumstances confirmed that the Lord was on his side.
7 Saül fut informé de l'arrivée de David à Keïla, et il dit: Dieu le livre entre mes mains, car il est venu s'enfermer dans une ville qui a des portes et des barres.