Revelation 4:7 NAS95 - 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.
WHY ONLY FOUR? St Ireneaus in Against Heresies (Book III, Chapter 11) - It is not possible that the Gospels can be either more or fewer in number than they are. For, since there are four zones of the world in which we live, and four principal winds, while the Church is scattered throughout all the world, and the “pillar and ground” 1 Timothy 3:15 of the Church is the Gospel and the spirit of life; it is fitting that she should have four pillars, breathing out immortality on every side, and vivifying men afresh. From which fact, it is evident that the Word, the Artificer of all, He that sits upon the cherubim, and contains all things, He who was manifested to men, has given us the Gospel under four aspects, but bound together by one Spirit. As also David says, when entreating His manifestation, “You that sits between the cherubim, shine forth.” For the cherubim, too, were four-faced, and their faces were images of the dispensation of the Son of God. For, [as the Scripture] says, “The first living creature was like a lion,” Revelation 4:7 symbolizing His effectual working, His leadership, and royal power; the second [living creature] was like a calf, signifying [His] sacrificial and sacerdotal order; but “the third had, as it were, the face as of a man,”— an evident description of His advent as a human being; “the fourth was like a flying eagle,” pointing out the gift of the Spirit hovering with His wings over the Church. And therefore the Gospels are in accord with these things, among which Christ Jesus is seated.
APOSTOLIC ERA KINGDOM DEVELOPMENTS: FROM JERUSALEM TO JONES CO MISSISSIPPI
1) JAMES (YAKOV BEN ZAVDI): Matthew's Gospel (the Ox)
2) PETER (CEPHAS): Mark's Gospel (the Lion)
3) SAUL OF TARSUS (PAUL): Luke's Gospel (the Eagle)
4) JOHN (YOHANAN BEN ZAVDI): John's Gospel (the Man)