Luke thesis statement comes at the very beginning:
Many have undertaken to draw up an account of the things that have been fulfilled[a] among us, 2 just as they were handed down to us by those who from the first were eyewitnesses and servants of the word. 3 With this in mind, since I myself have carefully investigated everything from the beginning, I too decided to write an orderly account for you, most excellent Theophilus, 4 so that you may know the certainty of the things you have been taught.
Luke, then, is an investigative reporter, and his dominant reason for writing his gospel is to create “an orderly account.” Luke’s purpose: order.
John is different. For one thing, he waits until near the end of his Gospel to tell us why he writes. For another thing, you’ll see that his reason for writing is much different than Luke’s. We find John’s purpose in 20:31:
31 But these are written that you may believe[a] that Jesus is the Messiah, the Son of God, and that by believing you may have life in his name.
John writes so that we “may believe” and through that belief discover “life in his name.” Unlike Luke, John doesn’t write for precision; he writes for persuasion.
Luke’s attention to detail and penchant for research allow him to uncover some gems that neither Matthew nor Mark include — in particular, the parables of the Good Samaritan and the Prodigal Son.
John’s bias for persuasion allows him to be … creative! … with his chronology. That’s why John’s account of the temple cleansing happens in chapter two, while in the Synoptics the same story occurs in the last week of Jesus’ life. Some folks have observed that phenomenon and said, ‘”Oh! There must have been two temple cleansings!” Such false harmony happens when you read the bible as a book and not a library. Taking the library approach, the interpreter realizes that purpose often determines form.
Luke is after order. John seeks persuasion.
And in the most interesting twist of all, I find Luke’s orderly account to be incredibly persuasive. I read the perfection of Luke 15 — lost sheep, lost coin, lost sons — and realize “that’s the God who found me when I wasn’t looking for him!”
By the same token, John’s persuasion is all the more compelling because of its order. In particular, I love how he builds the narrative around the I AM sayings, moving from the “I am he!” of 4:26 to the climactic “I am the resurrection and the life” of 11:25.
So I’m persuaded by order. And ordered by persuasion.
That’s worth a daily trip to the library in my book.