Isaiah 40:31

But those who wait for the Lord (who expect, look for, and hope in Him) will gain new strength and renew their power; they will lift up their wings (and rise up close to God) like eagles (rising toward the sun); they will run and not become weary, they will walk and not grow tired.   

When we trust the Lord in faith, we stop trying to accomplish our own miracles. When we believe God has heard our prayer and wait in faith for the answer. We rest and stop worrying because we have developed faith in the Word.