The Books of Enoch — True Church Edition
3 Enoch 36
The angels bathe in the fiery river before reciting the 'Song' R. Ishmael said: Metatron, the Angel, the Prince of the Presence, said to me :
1At the time when the ministering angels desire to say (the) Song, (then) Nehar di-Nur (the fiery stream) rises with many thousand thousands and myriads of myriads" (of angels) of power and strength of fire and it runs and passes under the Throne of Glory, between the camps of the ministering angels and the troops of 'Araboth.
2And all the ministering angels first go down into Nehar di-Nur, and they dip themselves in the fire and dip their tongue and their mouth seven times ; and after that they go up and put on the garment of 'Machaqe Samal’ and cover themselves with cloaks of chashmal and stand in four rows over against the Throne of Glory, in all the heavens.