1 Samuel 22:1-5 is an Old Testament illustration of the New Testament truth expressed by the Apostle in 1 Corinthians 1 that "God has chosen the weak things of the world to confound the things that are mighty."
David continues his run from Saul, only now he is no longer alone. Everyone in Israel who was discontented, in debt, and distressed have joined David in a cave outside of Adullam where he has become their leader.