Awake, awake, put on strength, O arm of the LORD; awake, as in the ancient days, in the generations of old. Art thou not it that hath cut Rahab, and wounded the dragon?
Awake! awake! put on strength, O arm of the Lord - Impassioned prayer of the exiled Jews.
Awake! as in the ancient days - (Psalms 44:1.)
(Art) thou not it that hath cut Rahab - poetical name for Egypt (note Isaiah 30:7).
(And) wounded the dragon? (Hebrew, taniyn (H8565)) - the crocodile, an emblem of Egypt, as presented on coins struck after the conquest of Egypt by Augustus; or rather here, its king, Pharaoh (note, Isaiah 28:1; Psalms 74:13-14; Ezekiel 32:2, margin; 29:3).