Revelation 14:2-3

2And I heard a sound from heaven like the roar of mighty ocean waves or the rolling of loud thunder. It was like the sound of many harpists playing together.

3This great choir sang a wonderful new song in front of the throne of God and before the four living beings and the twenty-four elders. No one could learn this song except the 144,000 who had been redeemed from the earth.