So with people of character, an impression has been left, and esp. I. Caleb had a God to live for. Regardless of religious background of Caleb, character begins in recognition of God. Higher power, higher purpose. Man is not of himself.
Real character comes from without and is built from within.
Also explanation of the ungodly who deny God, Rom. Caleb had a Faith to live by. Not enough to acknowledge God. Having a God to live for leads to having a faith to live by. Caleb was a man of faith.