What is the moral of Pulp Fiction?

It's about the discernment to recognize God's grace and wisely change course accordingly. Jules did while lunkhead Vincent didn't; "the wages of sin is death."

Because the theme of "redemption" plays a significant part in the faith of the characters. Jules kinda redeemed himself at the end when he decided he was done with the criminal life. Vincent, on another hand, didn't seem to have any intention to stop. So, he didn't redeemed himself and stayed a scumbag.

It's in the Bible verses and the entire conversation that Jules has with Ringo at the end. Every story in Pulp Fiction is about the Bible verses.

The world is evil and dark. Are there any shepherds in this world? Is there any redemption for anyone? The movie is looking for redemption, even for the most seemingly evil people.

Vincent, Butch, and Jules all become shepherds in one moment or another in their segments, despite themselves being criminals.
1) Vincent tries to save Mia's life after she overdoses (but only because her life meant his).
2) Butch is selfish, a liar and a manslayer. Yet, he's able to see the true horrors in those hill billy rapists and that no one should be subjected to that sort of torture. So he saves Marsellus, despite Marsellus trying to kill him earlier.
3) Jules is a hitman but decides not to kill anymore after witnessing a supposed miracle from God - why he doesn't kill Ringo and Lolanda. But Vincent is willing to kill more people and refuses to see anything more than his own ego. Jules through his miracle, was able to see more in life, more than his own ego. Thus redemption.

Jules' near-death experience made him reevaluate his life choices. He finalized that choice by sparing Ringo's life.

Vincent took the experience for granted and stayed the course of a reckless future. Butch proved just how perilous it could be.

If you restructure the movie to be in linear order, you see Vincent's life continue on a path of recklessness. After the diner and returning the briefcase, Jules leaves, but Vincent stays with it and is partly responsible for Mia's near death. Then not long after that Vincent gets shot in Butch's apartment.

Not only does Jules have a transitional moment, but Butch and Marcellus also have one where they put aside their hatred for each other. We didn't see enough of Mia to find out if the overdose changed her, but throughout everything we saw Vincent refusing to change.

No moral, just entertainment. If you want a message, call Western Union.

The universe sent them a little miracle/message. Jules got it, changed his way. Vincent didn't and died. Pulp Fiction is mostly "The Adventures of Morons" and Jules was the least dumb of the bunch.

Don't spoil it for me! I'm trying to forget what happened so I can watch it again fresh! Show some spoiler respect!

It's a rather religious movie, if you pay minimal attention to it.