Isaiah 40:28-31 (Amplified)
28Have you not known? Have you not heard? The everlasting God, the Lord, the Creator of the ends of the earth, does not faint or grow weary; there is no searching of His understanding.
29He gives power to the faint and weary, and to him who has no might He increases strength [causing it to multiply and making it to abound].
30Even youths shall faint and be weary, and [selected] young men shall feebly stumble and fall exhausted;
31But those who wait for the Lord [who expect, look for, and hope in Him] shall change and renew their strength and power; they shall lift their wings and mount up [close to God] as eagles [mount up to the sun]; they shall run and not be weary, they shall walk and not faint or become tired.