Isaiah 40:27-30

27Why do you complain, Jacob? Why do you say, Israel, “My way is hidden from the LORD ; my cause is disregarded by my God”?

28Do you not know? Have you not heard? The LORD is the everlasting God, the Creator of the ends of the earth. He will not grow tired or weary, and his understanding no one can fathom.

29He gives strength to the weary and increases the power of the weak.

30Even youths grow tired and weary, and young men stumble and fall;