1 John 1:1-4; 2 Peter 1:16-21
People wonder why there should be four books at the beginning of the New Testament telling what is essentially the same story.
Why is there not one exhaustive, chronological biography of the Lord Jesus Christ?
Why Four Gospels? The answer is very simple: these books were inspired by the Spirit of God and written by His chosen human penmen to meet specific needs.
They were addressed to real people in real situations who needed some specific aspect of the person and work of the Lord Jesus Christ to be emphasized to them.