Why have 4 gospels?
These different perspectives are more significant than simply coming together to weave a more rounded account of the life of Jesus though.
Matthew
Matthew, being a Levite, emphasizes Jesus as the Messiah, the Lion of the Tribe of Judah. Each of the subtleties of his design supports this primary theme. His genealogy begins with the "first Jew," Abraham, and continues through David and the royal line to the legal father of Jesus, Joseph. Matthew's emphasis is on the fulfillment of the prophecies of the Tenach, the Old Testament.Matthew focuses on what Jesus said, and includes the extensive discourses. Matthew's first miracle is the cleansing of a leper, a Jewish metaphor for sin itself. Matthew concludes with the resurrection, also a distinctive Jewish preoccupation.
Mark
Mark is the amanuensis (secretary) for Peter, and he emphasizes Jesus as the obedient Servant of YHWH. His is the only Gospel with no concern for pedigree or genealogy.For even the Son of man came not to be ministered unto, but to minister, and to give his life a ransom for many. - Mark 10:45 Mark focuses on what Jesus did; it deals in graphic images, almost like a movie or video shooting script. Mark concludes with the final visual appearance, the Ascension.
Luke
Luke was a Gentile and a doctor, and his Gospel reflects a very distinctive point of view, emphasizing Jesus as the Son of Man. His genealogy begins with Adam, the first man. From Abraham to David, his list is identical to that of Matthew. However, when he gets to David, he doesn't track through Solomon (the first surviving son of Bathsheba) but through a different son, Nathan (the second surviving son of Bathsheba). He continues through to Heli, the father of Mary (Joseph is the son-in-law of Heli). The term in Luke 3:23 is nomizo in Greek: reckoned as by law. Joseph was adopted by Heli in accordance to the exception in the Torah for inheritance through brotherless sisters given to Zelophehad (Numbers 27:1-11; Joshua 17:3-6; Ezra 2:61; Nehemiah 7:63; Numbers 32:41; 1 Chronicles 2:21-23, 34-35) As a Gentile, Luke's emphasis is different. Luke's emphasis is Christ's humanity, on what Jesus felt. His first miracle is the expulsion of a demon, a very human concern. Luke concludes with the promise of the giving of the Holy Spirit.
John
John also has a very distinctive view, emphasizing Jesus as the Son of God. He focuses on who Jesus was and is. His "genealogy" is that of the Preexistent One, constituting his opening verses: “In the beginning was the Word, and the Word was with God, and the Word was God.” His Gospel is organized around seven miracles, seven discourses, and seven "I AM" statements. John's first miracle involves the use of the water of purification being changed to wine at Cana, an act of Creation. John concludes with the promise of Jesus' return, and becomes the appropriate prequel to John's final tome, The Revelation.
The Four Faces Around the Throne
It is interesting that each time we encounter the cherubim or seraphim that surround the Throne of God, we note that there are four "faces" involved: a lion, an ox, a man, and an eagle (Ezekiel 1:10; 10:14; Revelation 4:7). These also were the principal tribal standards that rallied the four "camps" of Israel (each camp consisting of three tribes) that encamped around the Tabernacle (Numbers 2). Each of these "faces" are suggestive of each of the four Gospels: Matthew, presenting the Lion of the Judah; Mark, the ox (a classic emblem of servanthood); Luke, the Son of Man; and John, the Son of God in the heavens.