Revelation 4:6
Revelation 4:6 AMP
and in front of the throne there was something like a sea or large expanse of glass, like [the clearest] crystal. In the center and around the throne were four living creatures who were full of eyes in front and behind [seeing everything and knowing everything that is around them]. [Ps 99:1; Is 6:2, 3; Ezek 1:5, 18]