'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 slain, and hast redeemed us to God by thy blood, out of every tribe, and language, and people, and nation;

and a new song was sung before the throne, and before the four animals, and the elders: and no one could learn that song, but the hundred forty four thousand, who were ransom'd from the earth.