Each writer told the story for a particular audience and with particular emphases, and together they give a fuller portrait than one could.

Matthew writes with Jewish readers in view, Luke for a Gentile patron named Theophilus, and John states his purpose outright: so that readers will believe. The differences are deliberate, not a problem to be ironed out.

But these are written so you can believe that Jesus is the Messiah, the Son of God, and by believing, have life through him.

John 20:31

To compare a story with its parallels in the other Gospels, usually with a synopsis that sets them side by side.

The differences show what each writer chose to emphasise. The goal is not to merge the accounts into one, but to see what this writer is doing with a story the others also tell.

To read an episode in the flow of its own Gospel, asking why the writer put it where he did and how it connects to the stories around it.

Horizontal reading asks how the writers differ; vertical reading asks what this writer is saying through his arrangement. Both are needed, and vertical reading is the one most often skipped.

Mark starts one story, interrupts it with another, then finishes the first — so each interprets the other.

Jesus curses a fig tree, clears the temple, and then the disciples find the tree withered. Placed around the temple, the fig tree becomes a sign of judgment on a temple that looked alive and bore no fruit.

Mark 11:12-25

By their main points, drawn from the main characters and the story's surprise, in light of the audience Jesus was answering — not by finding a meaning in every detail.

Parables are realistic stories with a twist, and the twist is usually where the point is. Ask who Jesus was talking to and why; the setting Luke or Matthew gives a parable is often its best interpreter.

The hero is a Samaritan, and Jesus turns the lawyer's question from "who is my neighbour?" to "who acted as a neighbour?"

Jews and Samaritans despised each other. The lawyer wanted to know how far his obligation extended; Jesus made the despised outsider the example he had to follow.

Luke 10:29-37

As deliberate exaggeration meant to shock — take the point with full seriousness, but not the literal action.

"If your right eye causes you to sin, tear it out" is not an instruction to self-harm; nobody's left eye is innocent. It is a way of saying sin must be dealt with at any cost. Reading it literally misses the point, and so does softening it.

Matthew 5:29-30

Because they can be "seen together": they share much of the same material, often in the same order and with similar wording. John follows a largely different path.

Most scholars think Mark was written first and that Matthew and Luke used it. That is why comparing the three is so revealing: where Matthew or Luke changes Mark, you can see what they wanted to emphasise.

As the normal result of different writers telling the story for different readers — summarising, rearranging, and emphasising — rather than as errors to be explained away.

Ancient biographers were free to paraphrase speech and arrange events by topic rather than strict order. Their readers expected it. The differences usually show you what each writer was trying to teach.

It is built around a handful of signs and long discourses, includes Jesus' "I am" sayings, and says outright that it was written so readers would believe.

Much of what is in the Synoptics — parables, the exorcisms, the short sayings — is absent. What John includes, he develops at length. Reading John the way you read Mark misses that he has picked fewer events to say more about each.