When the Lamb comes out (Rev. 5), the elders sing (not "sung") a new song. Notice that the angels never sing. People make them sing, but they never do in Scripture. Angels shout and cry, but there is only one note found with them. Man has all kinds of infirmities, but he can be tuned; it takes such as man to be tuned. The angels shout and praise, and that is lovely. And they stand. And at the tomb, two angels sat. But these elders sing a new song.