We hear David exhausted and in pain. He sings that he is “sick at heart”. David is worn out from crying. He sings about how he feels and begs God to help. David turns the song to declare his belief that God has heard his cry and is going to rescue him. In Psalm 6 we read, “Save me because of Your unfailing love.” It’s a personal relationship based on the character of God, the nature of who God is. David depends on this. We rely on this.