Revelation 14:3-4

and they sing as it were a new song before the throne, and before the four living creatures and the elders: and no man could learn the song save the hundred and forty and four thousand, even they that had been purchased out of the earth. These are they that were not defiled with women; for they are virgins. These are they that follow the Lamb whithersoever he goeth. These were purchased from among men, to be the firstfruits unto God and unto the Lamb.