Revelation 4:6-8

6 And before the throne there was a sea of glass like unto crystal: and in the midst of the throne, and round about the throne, were four beasts full of eyes before and behind.

7 And the first beast was like a lion, and the second beast like a calf, and the third beast had a face as a man, and the fourth beast was like a flying eagle.

8 And the four beasts had each of them six wings about him; and they were full of eyes within: and they rest not day and night, saying, Holy, holy, holy, Lord God Almighty, which was, and is, and is to come.

The molten sea in the temple built by Solomon was the brass laver. It was here the priests came for their cleansing before they entered the holy place. It is turned to crystal in heaven because no one will ever need to confess their sins. The Church will be changed to be like Jesus and will be like stones of crystal whose lives are totally transparent to God and to others.

The word "beasts" in this passage is not a good translation. The Greek root word is  zwon  (zoon) where we get the word zoo. It should be translated as " living creatures ". These four living creatures are the Seraphim. The Seraphim are described in Isaiah 6:1-3. The faces of the creatures around the throne reflect the nature that God chose to reveal himself to His creation through His incarnation on earth and in His holy word. Among other things, the four faces of the Seraphim correlate to the four different testimonies of Jesus Christ in the gospels that show us God through His Son:

·Matthew...the lion (the King of the Jews and Messiah)

·Mark........the ox (the Servant)

·Luke........the man (the Son of Adam)

·John........the eagle (His heavenly origin)

The Seraphim continually tell of God's holiness. They say  holy, holy, holy  each time they praise Him because they are praising a  triune being.