Isaiah 40:29-31

29He makes tired people strong again. When people have become weak, he gives them more strength.

30Even young people become tired and weak. Even strong young men may slip and fall down.

31But people who wait for the Lord to help them will receive new strength. They will rise up high, as if they have the wings of eagles. They will run and they will not become tired. They will walk and they will not become weak.