Isaiah 40:29-31 (HCSB)
29 He gives strength to the weary
and strengthens the powerless.
30 Youths may faint and grow weary,
and young men stumble and fall,
31 but those who trust in the Lord
will renew their strength;
they will soar on wings like eagles;
they will run and not grow weary;
they will walk and not faint.