John the Apostle
Revelation 14:3ESV·traditional attribution

and they were singing a new song before the throne and before the four living creatures and before the elders. No one could learn that song except the 144,000 who had been redeemed from the earth.

Matthew Henry Presbyterian @wholebiblehenry

Here we have one of the most pleasing sights that can be viewed in this world - the Lord Jesus Christ at the head of his faithful adherents and attendants. Here observe, 1. How Christ appears: as a Lamb standing upon mount Zion. Mount Zion is the gospel church. Christ is with his church and in the midst of her in all her troubles, and therefore she is not consumed.

Commenting on Revelation 14:1-5

John Gill Reformed Baptist @doctorgill

And they sung as it were a new song,.... The song of redeeming grace; the same with that in Rev 5:9; see the note there: this is to be understood of the 144,000, who sung it before the throne, and before the four beasts and the elders; that is, publicly in the church, the ministers and members being present; of these; See Gill on Rev...

Albert Barnes Presbyterian @notesbybarnes

Verse 3. And they sung as it were a new song. . It was proper to call this "new," because it was on a new occasion, or pertained to a new object. The song here was in celebration of the complete redemption of the church, and was the song to be sung in view of its final triumph over all its foes. Compare Barnes on "Re 7:9"; .