Four Gospels? Why?

Why four Gospels? I've heard this question so many times. Few can answer this question better than A.W. Pink. From his introduction to Why Four Gospels we read


In Matthew, Christ is presented as the Son of David, the King of the Jews, and everything in his narrative centers around this truth. This explains why the first Gospel opens with a setting forth of Christ's royal genealogy, and why in the second chapter mention is made of the journey of the wise men from the East, who came to Jerusalem inquiring "Where is He that is born King of the Jews?", and why in chapters five to seven we have what is known as "The Sermon on the Mount" but which, in reality, is the Manifesto of the King, containing an enunciation of the Laws of His Kingdom.
In Mark, Christ is depicted as the Servant of Jehovah, as the One who through equal with God made Himself of no reputation and "took upon Him the form of a servant." Everything in this second Gospel contributes to this central theme, and everything foreign to it is rigidly excluded. This explains why there is no genealogy recorded in Mark, why Christ is introduced at the beginning of His public ministry (nothing whatever being told us here of His earlier life), and why there are more miracles (deeds of service) detailed here than in any of the other Gospels.
In Luke, Christ is set forth as the Son of Man, as connected with but contrasted from the sons of men, and everything in the narrative serves to bring this out. This explains why the third Gospel traces His genealogy back to Adam, the first man, (instead of to Abraham only, as in Matthew), why as the perfect Man He is seen here so frequently in prayer, and why the angels are seen ministering to Him, instead of commanded by Him as they are in Matthew.
In John, Christ is revealed as the Son of God, and everything in this fourth Gospel is made to illustrate and demonstrate this Divine relationship. This explains why in the opening verse we are carried back to a point before time began, and we are shown Christ as the Word "in the beginning," with God, and Himself expressly declared to be God; why we get here so many of His Divine titles, as "The only begotten of the Father," the "Lamb of God," the "Light of the world" etc.; why we are told here that prayer should be made in His Name, and why the Holy Spirit is here said to be sent from the Son as well as from the Father.

Pink, A. W. (2010-04-28). Why Four Gospels? - New Century Edition with DirectLink Technology (Kindle Locations 129-136). 99 Cent Books & New Century Books. Kindle Edition.

Thus we see here in brief the necessity of four Gospels. Download free or read online more from Pink here and enjoy your studying.