Why 4 Gospels?

Why not just one gospel?

The critical issue for any account of an event is evidence. The more witnesses the better. And better still if they have differing perspectives, that way you can be more sure that it is not a put-up job.

When police collect witness statements it gets very suspicious if they are the same, because everyone has a naturally different perspective. Same perspective points to collusion or fraud and raises the suspicion of just one witness giving a self-serving, and distorted report. This would probably be, in reality, an event in private and could be a complete fabrication

Such suspicion attaches to the Quran which was both 'revealed' in private and with circumstantial convenience, and the Book of Mormon, read by Joe Smith alone through magical glasses of gold tablets, which he did not and so probably could not produce!

 Still, a sucker is born every minute...both these 'authors' had  predilections for multiple wives and violence, that would also attract the suckers!

Now think about the witnesses of a traffic accident where a number of reports are prepared by those who saw the event or attended the scene for the police to use.

The vehicle removal operative would have a report that was about vehicles and their condition, their place on the road and what had to be done to remove them.

The ambulance crew would talk about the conditions of the injured, perhaps how they were extricated from the cars, what immediate medical aid was given and the hospital(s) to which they were transported.

The on-lookers would give very different views depending on their location when the accident happened, their familiarity with cars and their degree of shock. If they knew the injured or  not would also be a factor.

The  police report from the GD police would provide one perspective, the technical report in evidence from Accident Investigation another.

All reports would differ, but al about the same accident with differing perspectives and purposes.

So the Gospels.

Mark gives a short action-filled account for the average Jewish disciple, let's say.

Luke is interested in fine detail for an educated Greek readership.

Matthew concentrates on the theology and John writes with a more philosophical or spiritual interest for the more sophisticated Jew or Greek, perhaps.

Some different emphases are given by the writers for their different readers. Variously emphasizing this and sometimes that.

Differences don't mean contradiction, they mean different perspectives with different emphases.