Numeri 1:53

But the Levites shall pitch round about the tabernacle of testimony, that there be no wrath upon the congregation of the children of Israel: and the Levites shall keep the charge of the tabernacle of testimony.

Ver. 53. Shall pitch round about.] As the living creatures (the ministers) are between the four and twenty eiders, the congregation of the faithful, and the throne. Rev 4:4