Psalm 27:1 (ESV) … “The Lord is my light and my salvation; whom shall I fear? The Lord is the stronghold of my life; of whom shall I be afraid?”
Mark the personal pronouns. David’s confidence is based on personal experience. Over the years David had put God to the test in many a trying situation. He never found Him wanting!
Picture the prodigal with his pig-pail in that farmer’s lonely field in the country far from home. When he came to himself he came to his father as well. “My father’s servants are better dressed, better housed, better paid, better treated than I am here in this pagan land. I’m going home. I’m going to say to my father: ‘Father I have sinned … please give me a job. I don’t expect to be your son any longer. Just put me on the payroll as one of your hired hands.’ ” The prodigal dredged up from his memory long-forgotten thoughts of his father. Experience told him that his father would treat him with at least the gentleness and generosity he showed to his hired hands.
So David, in his hour of trial, based everything on his personal knowledge of God.