And before the throne was something like a sea of glass, as clear as crystal. In the center, around the throne, were four living creatures, covered with eyes in front and back.
We have here an account of a second vision with which the apostle John was favoured: After this, that is, not only "after I had seen the vision of Christ walking in the midst of the golden candlesticks," but "after I had taken his messages from his mouth, and written and sent them to the several churches, according to his command, after this I had...
Commenting on Revelation 4:1-7
And before the throne there was a sea of glass like unto crystal,.... By which is meant, not heaven, nor the souls of the blessed there, nor the multitude of the holy angels, nor the first converts to Christianity at Jerusalem; for those that got the victory over the beast are said to stand upon this sea, Rev 15:2, which these senses, especially the three...
Verse 6. And before the throne there was a sea of glass. An expanse spread out like a sea composed of glass: that is, that was pellucid and transparent like glass. It is not uncommon to compare the sea with glass. See numerous examples in Wetstein, in loc. The point of the comparison here seems to be its transparent appearance.