Revelation 14:2-5

And then I heard music, harp music and the harpists singing a new song before the Throne and the Four Animals and the Elders. Only the 144,000 could learn to sing the song. They were bought from earth, lived without compromise, virgin-fresh before God. Wherever the Lamb went, they followed. They were bought from humankind, firstfruits of the harvest for God and the Lamb. Not a false word in their mouths. A perfect offering.