3 They sang the song of Moses, the servant of God, and the song of the Lamb, saying, “Great and marvelous are your works, Lord God, the Almighty; Righteous and true are your ways, you King of the nations.
they sang the song of Moses, the bond servant of God – the deliverance of God’s people is similar to the deliverance of God’s people from Egypt. Being victorious they sing the song of Moses, the song the Israelites sang after God delivered them from Egypt.
and of the Lamb – here we have the song from two Covenants, the Song of Moses and the Song of the Lamb. The Song of the Lamb, as we discussed in Rev 14:3, is a song in the Spirit (the Lamb), as described in 1 Cor 14:15.
King of the nations – see Zech 14:9, and Rev 11:15, “in that Day the LORD shall be King over all the earth.”