Four Evangelists Symbols

Matthew the Evangelist, the author of the first gospel account is symbolized by a winged man, or angel. Matthew's gospel starts with Jesus' genealogy from Abraham; it represents Jesus' Incarnation, and so Christ's human nature.

Mark the Evangelist, the author of the second gospel account is symbolized by a winged lion - a figure of courage and monarchy. Mark has John the Baptist preaching "like a lion roaring" at the beginning of his Gospel. It also represents Jesus' Resurrection (because lions were believed to sleep with open eyes, a comparison with Christ in the tomb), and Christ as king. This signifies that Christians should be courageous on the path of salvation.^{[citation needed]}

Luke the Evangelist, the author of the third gospel account (and the Acts of the Apostles) is symbolized by a winged ox or bull - a figure of sacrifice, service and strength. Luke's account begins with the duties of Zacharias in the temple; it represents Jesus' sacrifice in His Passion and Crucifixion, as well as Christ being High priest (this also represents Mary's obedience). The ox signifies that Christians should be prepared to sacrifice themselves in following Christ.^{[citation needed]}

John the Evangelist, the author of the fourth gospel account is symbolized by an eagle - a figure of the sky, and believed to be able to look straight into the sun. John starts with an eternal overview of Jesus the Logos and goes on to describe many things with a "higher" level than the other three (synoptic) gospels; it represents Jesus' Ascension, and Christ's divine nature. This represents that Christians should look on eternity without flinching as they journey towards their goal of union with God.^{[citation needed]}

source: wikipedia

The Gospel symbols are based on the biblical imagery found in Ezekiel and Revelation.

The image of a man or angel represents the Gospel of Matthew and signifies Christ's human nature.

The lion represents the Gospel of Mark and is a traditional symbol of royalty and power and, therefore, denotes Christ the King.

The ox or calf, the sacrificial victim, represents the Gospel of St. Luke and highlights the priestly character of Christ's mission.

The eagle stands for the Gospel of St. John, the evangelist "who soars to the heavens," because his theology is much more developed than the three Synoptic Gospels. Just as an eagle soars above the earth, so John's theology soars above the other Gospels.

The symbols for the Synoptic Gospels probably come from how each one begins. The Gospel of Mark begins with the lines: "A voice cries out in the wilderness." In the wilderness you can hear the roar of the lion for miles around. Matthew's Gospel opens with the genealogy of Jesus, and represents Jesus' human roots. The Gospel of Luke opens with the story of Zechariah the high priest, who offered a sacrifice of a bull on behalf of the nation.

These symbols were developed as a way of helping people to remember the different Gospels and the perspectives that they took, especially at a time when most people could not read.

source: http://www.rc.net/philadelphia/st_patrick/symbols_of_the_four_evangelists.htm