David expresses, in Psalm 56, a mix between fear and faith. We see him processing his distress over the insatiable rage of the men perusing him. Through his fear, we see David repeating the refrain "when I am afraid I will trust...". He is recognizing his fear and letting it propel him forward, and thus he grows in trust. The key to bypass the debilitating nature of fear is to focus on The Word, and ultimately The Word incarnate. Christ and His sacrifice has freed us from the full debilitating power of fear.