REV 5:8

8 And when the SEH received the sefer, the Arbah Chayyot [(four living beings)] and the esrim v'arba'ah Zekenim[(twenty-four Elders)] fell down before the SEH[(Lamb)], each one having a nevel [(harp)] and golden ke'arot [(bowls)] full of ketoret [(incense)], which are the tefillos [(prayers)] of the Kedoshim.