Answer: Traditionally, the four Gospel writers have been represented by the following symbols: St. Matthew, a divine man; St. Mark, a winged lion; St. Luke, a winged ox; and St. John, a rising eagle.
These symbols are taken first from the Prophet Ezekiel (1:1-21):
“In the 30th year, on the fifth day of the fourth month, while I was among the exiles by the river Chebar, the heavens opened, and I saw divine visions. ... As I looked, a storm wind came from the North, a huge cloud with flashing fire, from the midst of which something gleamed like electrum. Within it were figures resembling four living creatures that looked like this: their form was human, but each had four faces and four wings, and their legs went straight down; the soles of their feet were round. They sparkled with a gleam like burnished bronze. Their faces were like this: each of the four had a face of a man, but on the right side was the face of a lion, and on the left side the face of an ox, and finally each had the face of an eagle ....”
In the Book of Revelation (4:6-8), we find a similar description:
“Surrounding this throne were 24 other thrones upon which were seated 24 elders; they were clothed in white garments and had crowns of gold on their heads. From the throne came flashes of lightening and peals of thunder; before it burned seven flaming torches, the seven spirits of God. The floor around the throne was like a sea of glass that was crystal-clear. At the very center, around the throne itself, stood four living creatures covered with eyes front and back. The first creature resembled a lion; the second, an ox; the third had the face of a man; while the fourth looked like an eagle in flight. Each of the four living creatures had six wings and eyes all over, inside and out. Day and night, without pause, they sing: ‘Holy, holy, holy, is the Lord God Almighty, He who was, and who is, and who is to come!’”
These images in both the Old Testament and the New Testament prompted
(140-202) to liken them to the four Gospel writers because of the content of their Gospels and their particular focus on Christ.
St. Irenaeus stated the first living creature was like a lion symbolizing His effectual working, His leadership, and royal power. He proposed that John's prologue concerning Jesus' divinely "royal" parentage marks that book as belonging to the regal animal, the lion.
St. Irenaeus indicated the second creature was like a calf or ox, signifying His sacrificial and sacerdotal order. Because Luke opens with a narrative involving priestly duties and temple services, Irenaeus associated it with the only sacrificial animal in the foursome, the ox.
The third creature had the face like man, an evident description of His advent as a human being.
St. Irenaeus saw
Matthew as corresponding to the man's face because it opens with a human genealogy of Jesus and because, in the view of Irenaeus, Jesus' humanity is emphasized throughout the book. The final creature was like a flying eagle, pointing out the gift of the Spirit hovering with His wings over the Church.
St. Irenaeus linked the early mention of Holy Spirit in Mark with the winged creature, the eagle.
The wings on all of the symbols of the gospels are to symbolize their connection to the divine, like eagle wings or angels (who were the messengers of God) they deliver this story and good news.