Revelation 14:2-4

2And I heard a voice from heaven, like the voice of many waters, and like the voice of loud thunder. And I heard the sound of harpists playing their harps.

3They sang as it were a new song before the throne, before the four living creatures, and the elders; and no one could learn that song except the hundred and forty-four thousand who were redeemed from the earth.

4These are the ones who were not defiled with women, for they are virgins. These are the ones who follow the Lamb wherever He goes. These were redeemed from among men, being firstfruits to God and to the Lamb.