'New Song' in the Bible

and they sung a new song saying, "Thou art worthy to take the book, and to open the seals thereof, for thou wast killed, and hast redeemed us by thy blood, out of all kindreds, and tongues, and people, and nations,

And they sang as it were a new song, before the seat, and before the four beasts, and the elders and no man could learn that song, but the hundred and forty four thousand which were redeemed from the earth.