Revelation 14:1-3

1Then I looked and saw the Lamb standing on Mount Zion, and with Him 144,000 who had His name and His Father’s name written on their foreheads. 2And I heard a sound from heaven like the roar of many waters and the loud rumbling of thunder. And the sound I heard was like harpists strumming their harps.

3And they sang a new song before the throne and before the four living creatures and the elders. And no one could learn the song except the 144,000 who had been redeemed from the earth.