'Pouring out the vials upon the earth, which contained the plagues,' in Revelation 16:1, signifies influx of the reformed into the church, or into people who study and receive the doctrine of justification by faith alone.

(Reference: Apocalypse Explained 16; Apocalypse Revealed 676)

617. 14:3 They sang as it were a new song before the throne, before the four living creatures, and before the elders. This symbolizes a celebration and glorification of the Lord in His presence and in the presence of the angels of the higher heavens.

Their singing a new song symbolizes an acknowledgment and glorification of the Lord as being the only Judge, Redeemer, and Savior, thus God of heaven and earth, as may be seen in no. 279 above. Before the throne means in the Lord's presence, because He alone sits upon the throne. Before the four living creatures and before the elders means in the presence of the angels of the higher heavens (no. 369).

As it were a new song symbolizes a celebration and glorification of the Lord in the New Christian Heaven. Here specifically it means that He was acknowledged as God of heaven and earth, as He is acknowledged in the ancient heavens. This is entailed in the phrase "as it were," for "as it were a new song" means that it was seemingly new, when in fact it was not new.

We have already said before that the new heaven spoken of in Revelation 21:1 is a new heaven formed of Christians, that the prior heavens were formed of ancient peoples and most ancient ones, and that in those heavens the Lord is acknowledged as God of heaven and earth.