Rev 15:3-4
"And they sang the song of Moses, the servant of God, and the song of the Lamb, saying, ‘Great and amazing are your deeds, Lord God Almighty! Just and true are your ways, O King of the saints! Who will not fear, O Lord, and glorify your name?’"
The song of Moses (Exodus 15 — victory at the Red Sea) + song of the Lamb = the definitive Exodus. The victors sing before judgment — the certainty of victory is so great that worship precedes fulfillment. The attributes of God: marvelous works, just and true ways, King of the saints.