Revelation 4:6
6
Before the throne was something like a sea of glass, similar to crystal. In the midst of the throne, and around the throne were four living creatures full of eyes before and behind.
Apocalypse Explained #40
40. Even so, Amen, signifies Divine confirmation that so it will be. This is evident from the signification of "even so," as being a confirmation of what goes before, that so it will be; and from the signification of "Amen," as being Divine confirmation (See above, n. 34).