Revelation 15:3 - Matthew Poole's English Annotations on the Holy Bible

And they sing the song of Moses the servant of God; the song which Moses sang upon God's delivery of the Israelites from the danger of Pharaoh, which we have, Exodus 15:1-27; not that they sang those words, but to the same sense. And the song of the Lamb; a song to the honour of Christ, to the same sense that Moses sang, and upon a much like occasion. Saying, Great and marvellous are thy works, Lord God Almighty; admiring the greatness and marvellousness of what God had done in their deliverance, and giving him the glory of his Almighty power. Just and true are thy ways, thou King of saints; acknowledging, that all the acts of his providence were both just, God in them giving to every one their due, and true, God by them but justifying his promises and threatenings. These words are taken out of Psalms 145:17.