“And they sing the song of Moses the servant of God, and the song of the Lamb, saying, Great and marvelous are thy works, Lord God Almighty; just and true are thy ways, thou King of saints.” (Revelation 15:3, Webster)

This is the song given to us in Deuteronomy  32:1–43; it is recorded that Moses wrote this song and taught it to the people, as seen in Deuteronomy 31:22. This is the second song, the song of the Lamb, and begins with the Crucifixion, which was absolutely necessary if man was to be redeemed, and closes with Jesus Christ as “King of kings, Lord of lords”
Great are your works Lord God Almighty refers to Christ; while all His Works are “great and marvelous,” what He did at the Cross presents itself as the greatest work of all.
Christ is our King by virtue of what He did at the Cross, and our Faith in that Finished Work.

What a mighty God We Serve

Another beautiful showing of the continuity between the Old and New Covenants through song and worship.In Revelation, the “song of Moses” and the “song of the Lamb” symbolize both deliverance and redemption. The first celebrates Israel’s rescue from Egypt; the second celebrates humanity’s redemption through Christ’s sacrifice.
This parallel proves that just as God brought Israel through the Red Sea, He now brings believers through to salvation by the blood of the Lamb. Visually, the Red Sea becomes a symbol of the Cross itself: in both, a path through death leads to life. Moses raised his staff; Christ was lifted on the Cross, seen in both moments are divine interventions  resulting in salvation for any who truly believe on Christ.
The Cross was the climax of Christ’s earthly mission, yet also the axis point of all of God’s redemptive works. It transforms judgment into mercy and defeat into victory hence the praise: “Great and marvelous are thy works.”

Indeed, what a mighty God we serve.