Revelation 4:6-11

Four Living Creatures

6 Before the throne was something like a sea of glass, like a crystal. In the midst of the throne, and around the throne were four living creatures full of eyes before and behind.7 The first creature was like a lion, and the second creature like a calf, and the third creature had a face like a man, and the fourth creature was like a flying eagle. 

Rev 4:6-7
four living creatures – these are the four living creatures from Ezekiel 1:10. The slight difference is the creatures in Ezekiel shared four attributes among four creatures, all of whom had the face like a man. In Revelation, these creatures are said to be four separate creatures: with faces like a lion; a calf; a man; and an eagle. These four creatures represent the saints of the four periods of the kingdom of heaven:

A lion (33 to 193) – the Apostolic saints, the first of whom was Christ, “the male Child,” called “the lion of Judah,” see Rev 5:5.
A calf or ox (193 to 1471)– the kingdom of heaven in the wilderness, grazing, “to be nourished for time, time and half a time from the presence of the serpent” (Rev 12:14). A calf and ox represent those to be sacrificed, as we read in Exodus 20:24, and Micah 6:6. This is an appropriate representation of the Martyrs in this period.
A man (1471 to 1917) – the thinking and studying man. The saints who escape from mystery Babylon must study the Bible to restore the truth of Christ and the Apostles.

In Daniel 7:4, King Nebuchadnezzar was represented as a lion, with the wings of an eagle, and was made to stand on two feet like a man, and a human mind was given to it. In Daniel 4:16, we read, “let his heart be changed from that of a man, let him be given the heart of a beast.” Nebuchadnezzar was made a beast, until he recognized “that the most High rules in the Kingdom of men” (Daniel 4:25-26). In Daniel 3:4-5, he forced all peoples and nations and tongues to worship an image, but in Daniel 4:1-3, he repented and praised God, to “every people, nation, and tongue.” This foreshadowed the Angel’s proclamation in Revelation 14:6-7, to “every nation, and tribe and tongue and people, and he said with a loud voice fear God and give Him glory.” In summary, the beast must become a man and learn to recognize the true God.
An eagle (1917 AD to the Lord’s Day)– the saints of the end days, the sanctified Church, soaring with the power of the Spirit, and looking down from high, understanding all things, including the Book of Revelation. The eagle is very well explained in Isaiah 40:29-31. The Bible gives us several proofs that the eagle is the last living creature: most notably Jesus’ quotation of Isaiah, “where the corpse, there the eagles aetoi will be gathered” (Matthew 24:28). This describes the gathering together of the saints in the Lord’s Day, by the Spirit of Christ (see Isaiah 34:15,16). The eagle is the end time saint who flies “in mid-heaven” warning the world of the threes woes to come (Rev 8:13), and the eagles must also be “the birds which fly in mid-heaven,” who eat the flesh of the Nations, at the command of the Rider on the White Horse in Rev 19:17-18. The “flying” of the eagles represents the speed at which the end time Church brings the true gospel to the world.

Understanding the time periods of these saints helps us understand the time periods of some prophecies, especially in Chapters 6 and 8 of Revelation.

8 and the four living creatures, having each one of them six wings, are full of eyes around about and within. They have no rest day and night, saying, Holy, holy, holy is the Lord God, the Almighty, who was and who is and who is to come. 

Rev 4:8
Holy, holy, holy – some early texts, and the Majority text lists nine holys, for the Almighty God. This is compared to the three holys in Isaiah 6:3, applied to the Spirit of Christ, as the YHVH (He WILL BE) of Hosts .

Holy, holy, holy (WHO WAS)
Holy, holy, holy (WHO IS)
Holy, holy, holy (WHO IS TO COME)

9 When the living creatures give glory, honor, and thanks to him who sits on the throne, to him who lives forever and ever,10 the twenty-four elders fall down before him who sits on the throne, and worship him who lives forever and ever, and will throw their crowns before the throne, saying, 

Rev 4:9-10
cast their crowns before the throne – the crown of victory that is received by all the saints who overcome, and are victorious, see Rev 3:11.