And they sung a new song, saying. They sing; the worship is unceasing. The song is new because it is only now, subsequent to the accomplishment of Christ's work of redemption, that the song can be sung.
It is not" Thou art worthy, for thou wilt redeem," but "thou didst redeem." Victorinus says, "It is the preaching of the Old Testament together with that of the New which enables the world to sing a new song."
Thou art worthy to take the book, and to open the seals thereof. (For a consideration of the book, and the opening of it, see on Revelation 5:1.) For thou wast slain, and hast redeemed us to God by thy blood.
The reason why Christ is worthy. And didst redeem unto God by thy blood out of every kindred, etc. Though the reading "us" is supported by various manuscripts, and similarly the first person is used in Revelation 5:10.
yet, on the whole, it seems better to omit it, the phrase being taken in a partitve sense—"Thou didst redeem unto God by thy blood some out of every kindred, etc., and hast made them, etc., and they shall reign."
Again, "Thou didst purchase us at the price of thy blood" would, perhaps, give the sense more correctly; for such is the force of the words, "in thy blood" ( ἐν τῷ αἵματι). The words point to a particular act performed at a definite time, viz.
the death of Christ, by which he repurchased men from sin and Satan for the service of God; the price of the purchase being the shedding of his own blood. The words show, too, that the fruits of the redemption are intended for the whole world; not limited to any chosen nation, though some are excluded by their own act.
Out of every kindred, and tongue, and people, and nation. This fourfold classification continually recurs in the Revelation. It includes all the bases of classification of mankind, all the circumstances which separate men, the barriers which were overthrown by the redeeming work of Christ.