Rev 5:9

“If I remember not that it is I who have served Him, how shall I ascribe glory to God? How sing to Him "the new song," if I am ignorant that it is I who owe Him thanks? But why is exception taken only against the change of the flesh, and not of the soul also, which in all things is superior to the flesh? How happens it, that the self-same soul which in our present flesh has gone through all life's course, which has learnt the knowledge of God, and put on Christ, and sown the hope of salvation in this flesh, must reap its harvest in another flesh of which we know nothing? Verily that must be a most highly favoured flesh, which shall have the enjoyment of life at so gratuitous a rate! But if the soul is not to be changed also, then there is no resurrection of the soul; nor will it be believed to have itself risen, unless it has risen some different thing.”

“Christ wrote a new song by the harmonious truth of both Testaments. This he did when he, remaining the Word which was in the beginning, was born by a new sort of birth through the Virgin. This he did when he as God put on man in a new manner. This he did when he gave himself over to his killers by his own power. This he did when he was wondrously made alive from the dead and when at a time of his own choosing was ascended beyond the heavens. And this new song he bestowed upon all those who belong to the church which he acquired, that it might be sung continually, and that in this [the church] might rest secure as it awaits in hope the coming judge, that "we might walk in the newness of life." As he said, "If any one wishes to be my disciple, let him deny himself and take up his cross and follow me."”

“Through this passage it is revealed that the elders, both those in the Old Testament and those in the New Testament, were well-pleasing to God, and that on behalf of the whole world they bring forth a [hymn of] thanksgiving to the Lamb of God who was slain and redeemed us. It is a "new song," which we have been taught to sing, who from every tribe and tongue have been freed from the antiquity of the letter and through the Spirit have received light. He says that these will rule the new earth, which the Lord promised to the humble.”

“And you have redeemed us to God by your blood, etc. Here it is further declared that the creatures and elders are the Church, which has been redeemed by the blood of Christ and gathered from the nations. It also shows in which heaven they are, by saying: And they will reign on the earth. And I saw and heard the voice of many angels around the throne, and the creatures, and the elders.”

“And they sung a new canticle, saying: Thou art worthy, O Lord our God, to take the book, etc. Christ sang a new canticle by preaching it in words and following it in acts. Now what does it mean to say, Thou art worthy, O Lord our God, to take the book, and to open the seals thereof; because thou wast slain, and hast redeemed us to God, in thy blood, out of every tribe, and tongue, and people, and nation, if not "Compared to our victories, thy victory alone is considered one, by which we were redeemed from the prince of death and the malediction of the law?" By the fact that the four living creatures and the twenty-four ancients say they have been redeemed out of every tribe, and tongue, and nation, it is clearly shown that by them is represented the universal Church.”

“And they sang a new song. For the song sung to God incarnate is new, having never before been brought forth prior to the incarnation. What was the song? Worthy are You, it says, "to bring this salvation to mankind, you who were slain for us and by your blood have redeemed many from under the heavens." And he certainly spoke very securely from every tribe and language and people and nation. For he did not acquire all, for many died in unbelief, but from all those worthy of salvation. The prophet also said: "Arise, O God, judge the earth, for you shall judge all the nations; indeed, you will not condemn all the nations." (Ps. 81:8)”