Isaiah 40:28-31

28Do you not know? Have you not heard? The Everlasting God, the LORD, the Creator of the ends of the earth does not become weary or tired, His understanding is inscrutable. 29He gives strength to the weary, and to him who lacks might He increases power. 30Though youths grow weary and tired, and vigorous young men stumble badly, 31Yet those who wait for the LORD will gain new strength; they will mount up with wings like eagles, they will run and not get tired, they will walk and not become weary.