Revelation 2:17

2:17 The one who has an ear had better hear what the Spirit says to the churches. To the one who conquers, I will give him some of the hidden manna, and I will give him a white stone, and on that stone will be written a new name that no one can understand except the one who receives it.’

Revelation 14:3

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.