Thematic Bible: Alone can learn the songs of heaven

And they [i.e., the 144,000] were singing a new song in front of God's throne, and in front of the four living beings and the [twenty-four] elders. No one could learn [to sing] this song except the one hundred and forty-four thousand [See 7:4,9] who had been purchased from the earth. These people are the ones who did not practice sexual immorality with women, for they were virgins [Note: This probably has reference to people who avoided idolatry]. These are people who followed the Lamb wherever He went. They were purchased from among mankind to be the firstfruits [devoted] to God and to the Lamb.