Revelation 4:5-8 meaning

John's vision continues as he is in the throne room of God. He moves from describing the thrones to describing what else in the room, continuing his description is a multi-sensory experience: Out from the throne come flashes of lightning and sounds and peals of thunder (v 5). This is not just a vision of visuals, but one with sounds too. 

It seems John is having the sensation of being in a cloud where a thunderstorm is in full swing, with lightning as well as thunder. Put together with the rainbow from Revelation 4:3, it seems this throne room is encompassed with many atmospheric spectacles. However, there does not seem to be any chaos—these appear to be tamed lightning and thunder. 

Next, John describes that there were seven lamps of fire burning before the throne, which are the seven Spirits of God (v 5). These seven lamps are the same that we saw in Revelation 1: 

"I saw seven golden lampstands; and in the middle of the lampstands I saw one like a son of man, clothed in a robe reaching to the feet, and girded across His chest with a golden sash."
(Revelation 1:12-13)

And at the end of Chapter 1, it is revealed that "the seven lampstands are the seven churches" (Revelation 1:20). The lampstands are the churches, and there is fire burning on these lamps, which is the Spirit. This indicates that John's vision is full of imagery. It could be that God is giving John a picture he can understand and describe; it would seem likely that John might not survive seeing the real thing (Exodus 33:20). 

John continues: before the throne there was something like a sea of glass, like crystal (v 6). That John says there was something like would indicate that he is trying to use things previously familiar to describe things he had not seen previously. In front of God's throne there is something like a sea of glass. The sea is often used in scripture as a picture of worldly chaos. In Chapter 13, we will see the Beast (or antichrist) arise from the sea. The picture here seems to be that God on His throne is One who tames the sea. He is over all. Before Him the sea is calm, like a sea of glass. 

John continues now describing some bizarre creatures: and in the center and around the throne, four living creatures full of eyes in front and behind (v 6). These creatures are described as having eyes in front and behind, and they surround the throne. This could be angelic creatures who keep watch over the earth. We are told that children have angels watching them who are in God's presence:

"See that you do not despise one of these little ones, for I say to you that their angels in heaven continually see the face of My Father who is in heaven."
(Matthew 18:10)

It could be that these creatures are those who continually see and watch over things on the earth. It seems from this passage in Matthew that these angels can watch over children and be in God's presence at the same time. This could be what is represented by the many eyes. It could be that angels can take various forms. 

John now describes several types of creatures:

The first creature was like a lion, and the second creature like a calf, and the third creature had a face like that of a man, and the fourth creature was like a flying eagle. And the four living creatures, each one of them having six wings, are full of eyes around and within (vv 7-8a). 

The first creature that was like a lion might indicate power, like the "king of beasts" on earth. It could be that this indicates power to fight. God is often referred to as the Lord of hosts, which can also be translated as God of armies. This creature like a lion could indicate angels that fight for God. Later in Revelation we will see a war break out in heaven (Revelation 12:7). Jesus said that He could summon twelve legions of angels to fight on His behalf (Matthew 26:53). 

The second creature with the face like a calf could symbolize provision. Calves were used to celebrate and to sacrifice. It could be that some angels are used to care and to connect. God is the provider for His people. He is sometimes called "Jehovah Jireh" which is "The LORD will provide" (Genesis 22:14). 

The third creature that has the face of a man could indicate that God uses some angels to engage with humans in a manner that cannot be easily detected, as indicated in a number of stories in the Old Testament (Genesis 19:1; Hebrews 13:2). 

The fourth creature was like a flying eagle. This could indicate God's active engagement with those on the earth, as eagles fly high and see all. Interestingly, these creatures in God's presence constantly echo the same refrain: 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" (v 8b). 

The creatures around the throne are speaking, something that we are not used to animals, or creatures, doing. The word used for creature here means "beast" or "animal," and it is used in the Bible to refer to the animals that are sacrificed. So why can they speak? 

Psalm 19 says: 

"The heavens are telling of the glory of God;
And their expanse is declaring the work of His hands.
Day to day pours forth speech,
And night to night reveals knowledge."
(Psalm 19:1-2)

The psalmist continues, saying that the heavens are speaking, "declaring," the glory of God's creation. In John's vision, he can hear what the creatures are saying, and they are saying the same thing as all God's creation says continually—but in this case their declaration is audible to him. They are saying Holy, holy, holy is the Lord God, the Almighty, who was and who is and who is to come (v 8b).

It seems likely, based on Psalm 19, that all things are proclaiming Holy, holy, holy is the Lord God and proclaiming His glory—we just can't audibly perceive it at this point. But perhaps in the next life we will be able to. 

What are these creatures that are telling of God's glory? They seem to match Ezekiel's descriptions of cherubim: 

"Each of them had four faces and four wings. Their legs were straight and their feet were like a calf's hoof, and they gleamed like burnished bronze. Under their wings on their four sides were human hands. As for the faces and wings of the four of them, their wings touched one another; their faces did not turn when they moved, each went straight forward. As for the form of their faces, each had the face of a man; all four had the face of a lion on the right and the face of a bull on the left, and all four had the face of an eagle. Such were their faces. Their wings were spread out above; each had two touching another being, and two covering their bodies…the rims of all four of them were full of eyes round about."
(Ezekiel 1:6-11, 18)

It is revealed later in Ezekiel 10 that these creatures described in Ezekiel are called cherubim (Ezekiel 10:1). They bear a striking resemblance to the creatures in Revelation 4. They are both full of eyes around and within, have multiple wings (the ones in Ezekiel having four and the ones in Revelation having six), and resemble the same four animals, a lion, calf, man and eagle (the one in Ezekiel having a face of each and the four creatures in Revelation each resembling one of them). 

If these creatures are so similar to cherubim, we might wonder why they are not referred to as cherubim. Perhaps they are similar, but not the same. But since cherubim are a kind of angel and these are referred to as creatures perhaps there is a large variety of angelic beings, similar to the wide variety of creatures in the animal kingdom. 

The fact that these non-human creatures speak audibly indicates that there will be a spectrum of language-capable creatures in the new earth.