Revelation 4:6, 8

and before the throne there was something like a sea of glass, like crystal; and in the center and around the throne, four living creatures full of eyes in front and behind.

And the four living creatures, each one of them having six wings, are full of eyes around and within; and day and night they do not cease to say, “HOLY, HOLY, HOLY is THE LORD GOD, THE ALMIGHTY, WHO WAS AND WHO IS AND WHO IS TO COME.”