Revelation 14:2-3

RKJNT(i) 2 And I heard a voice from heaven, like the sound of many waters, and like the roar of great thunder: the voice I heard was like the sound of harpists playing upon their harps: 3 And they sang a new song before the throne, and before the four living creatures, and the elders: and no man could learn that song but the hundred and forty-four thousand, who had been redeemed from the earth.