Revelation 14:3-4

14:3 and they were singing a new song before the throne and before the four living creatures and the elders. No one was able to learn the song except the one hundred and forty-four thousand who had been redeemed from the earth.

14:4 These are the ones who have not defiled themselves with women, for they are virgins. These are the ones who follow the Lamb wherever he goes. These were redeemed from humanity as firstfruits to God and to the Lamb,