And they sing as it were a Shir Chadash before the kisseh and before the Arbah Chayyot and the Zekenim, and no one was being able to learn the Shir except the 144,000, the ones for whom the  [kapparah] price had been paid for their Geulah [Vayikra 5:50-51] redemption, the ones having been purchased from kol ha'aretz.