“Now when He had taken the scroll, the four living creatures and the twenty-four elders fell down before the Lamb, each having a harp, and golden bowls full of incense, which are the prayers of the saints. And they sang a new song, saying:

‘You are worthy to take the scroll,
And to open its seals;
For You were slain,
And have redeemed us to God by Your blood
Out of every tribe and tongue and people and nation’”
Revelation 5.8-9

The proclamation of the Old Testament associated with the New, points out the Christian people singing a new song, that is, bearing their confession publicly. It is a new thing that the Son of God should become man. It is a new thing to ascend into the heavens with a body. It is a new thing to give remission of sins to men. It is a new thing for men to be sealed with the Holy Spirit. It is a new thing to receive the priesthood of sacred observance, and to look for a kingdom of unbounded promise. The harp, and the chord stretched on its wooden frame, signifies the flesh of Christ linked with the wood of the passion. The phial signifies the Confession and the race of the new Priesthood. But it is the praise of many angels, yea, of all, the salvation of all, and the testimony of the universal creation, bringing to our Lord thanksgiving for the deliverance of men from the destruction of death. The unsealing of the seals, as we have said, is the opening of the Old Testament, and the foretelling of the preachers of things to come in the last times, which, although the prophetic Scripture speaks by single seals, yet by all the seals opened at once, prophecy takes its rank.

St Victorinus of Pettau, Commentary on the Apocalypse of the Blessed John [On Revelation Ch. 5, vv. 8-9]