Revelation 4:6, 8

and before the throne, as it were a sea of glass like unto crystal; and in the midst of the throne, and round about the throne, four living creatures full of eyes before and behind.

And the four living creatures, having each one of them six wings, are full of eyes round about and within: and they have no rest day and night, saying, Holy, holy, holy, is the Lord God, the Almighty, who was and who is and who is to come.