'New Song' in the Bible

Then they sang a new song: "You deserve to take the book and break its seals, because you have been slaughtered, and with your blood have bought men from every tribe, tongue, people, and nation,

They were singing a new song before the throne, the four living creatures, and the elders, and no one could learn the song except the hundred and forty-four thousand who had been redeemed from the earth.