I can't disagree strongly enough that this is not a moralistic take on the prophet needing to avoid an unmentioned previously sinful life. There is nothing in the text to suggest this. This story is about the cutting off of Bethel, and the prophet is merely a prop, without even a name, that appears in the middle of the story to reveal what is going to happen to Bethel.
## Context
Please read the preceeding context, from 12:25-33.
Summarizing:
Jeroboam, king of the Israel, was afraid he would lose the kingdom as long as his population kept going to Jerusalem in Judah for the mandatory feasts. Remember that anyone not going to these was cut off. Also, whenever there was a trespass offering or other offering that needed to be given, since it could only be given at the Jerusalem temple, it was done at the next mandatory feast. Obviously that's a problem if your entire kingdom's religious administration is controlled by another country to the south, one that you are rivals with. So he deciced to set up alternate worship sites in his own country, in the old high places of Dan and Bethel (where Jacob saw the dream of the ladder).
## Background on the high place at Bethel
Now Bethel was a place where the ark rested for a time (Judges 20.27), and there were priests in Bethel that were descended from the days when it was acceptable to worship there. For over a thousand years, beginning when Abram built an altar east of Bethel in Genesis 12.8 and then dwelt there after returning from Canaan in Gen 13.3. Jacob's dream of the ladder was at Bethel and "the God of Bethel" spoke to him in Gen 31.13.
until the temple was dedicated (977 BC), Beth El was a legit sacred place that was important to most of the heroes of Israeli history. It was where people worshipped, creating an established society of priests, prophets, etc.
But when the Temple was inaugurated by Solomon, the priests could no longer sacrifice at Bethel as all sacrifices moved to the temple in Jerusalem. That turned the shrine at Bethel into an idolatrous high place. But prophets were still allowed to prophecy in all places, however when the golden calf was placed in Bethel, God cut off the entire religious establishment. This story is about this separation and reveals some of the social and spiritual consequences of it.
Note that as The temple was only dedicated about 50 years before, so much of the infrastructure and people (hence the "old prophet") were still around for this story.
It was this practice (pre-Temple worship) that Jeroboam was trying to revive as an alternative to temple worship, and if you were going to pick a #2 city in terms of importance and holiness, then Bethel would be there, right behind Jerusalem. This is why Jeroboam picked it. He even put a golden calf there and led worship of the calf.
## The unnamed prophet of God.
This prophet appears unexpectedly (hinneh!) in the narrative. All we know is that he is from Judah. Thus he is a representative of prophets in Judah. He prophesizes the slaughter of the existing priests at Bethel and the destruction of the shrine there. But in addition to this obvious condemnation of a shrine on which the golden calf was being worshipped, he is *also* given two commandments, which are important for the rest of the religious community at Bethel.
* Don't return by the path you came
This should be viewed as nothing more than an intensive form of "Never return to Beth-El when you leave it".
The idea is not just, don't go back to the city boundaries once you exit, but *don't go back to the city or any place within the city*. E.g. if we imagine Bethel is a single road, with houses numbered 1 to 10
and the shrine is at 5.
Bethel: 1 2 3 4 5=shrine 6 7 8 9 10
Say the prophet came to the shrine from house 1, so he is moving right. Then finally he arrived at the shrine at house 5. Then he pronounces the fate of the shrine. Now if he were to turn around and go back down the same road, he would visit house 4 twice! And same for house 3, etc. *Thus he would be "returning" to a place in Bethel.*
But the prohibition was very strict, to never return to Bethel, and so that meant he had to exit the city via a different route. *There would only be one visit from God, as this was a message of irrevocable separation between God and the religious infrastructure of the city* and once you divorce something you can never have fellowship with it again. There was to be no more contact between the apostate religous leaders and the prophet of God.
A similar prohibition was given to Lot's wife (Gen 19.26) -- she was not allowed to look back at Sodom. When something is condemned, you are not supposed to ever go back to it. But it was not the *prophet* or his past life that was condemned, *it was Bethel*, specifically the religious community within Bethel that had been declared apostates.
That's all that's going on here with the different routes.
* Don't eat or drink in Bethel
Here the idea is of communion or a peace offering. When a messenger of God shares a meal with someone, that is symbolic of enjoying fellowship with them, which again was not allowed in this divorce visitation.
## The Old Prophet
The Old Prophet, supposedly from a time when Bethel was a true center of worship, is worried about this cutting off, so he wants to test if it applies to him as well.
Perhaps the prohibition on fellowship was only against the king and priests of the shrine, but not against him and his people, the descendents of prophets of God. After all, while it's true that priests can only perform sacrifices at Jerusalem, prophets can still prophesy wherever they are. Or can they? The old prophet longed for that communion, so he tricked the unnamed prophet into having a meal with him to see if fellowship was still possible between these two groups.
It was not, the spirit of God came on the old prophet and the unnamed prophet was condemned and then shortly killed by God, with a lion and the old man's donkey standing on either side of the corpse (the lion is symbolic of Judah and the donkey of prophets). The message was clear - God would destroy any prophet of Judah who tried to have fellowship with the old prophets of Bethel. Death was to be the only fellowship between the two groups. This is why the old prophet is so sorrowful - he is not sad about the death of this stranger whom he tricked, but about the finality of God's decision to divorce him and his people.
> For surely, the thing which he proclaimed by the word of Yahweh
> against the altar which is in Bethel will happen, as it will against
> all the houses of the high places which are in the cities of Samaria.”
> 1 ki 13.32 LEB
Longing for that togetherness, he calls the prophet "my brother" and instructs to place him in his own tomb, asking that his own body be placed next to his, so that at least in death they can embrace each other.
> He put his corpse in his tomb, and they mourned over him, “Alas, my
> brother!” It happened after he buried him that he said to his sons,
> “When I die, you shall bury me in the tomb where the man of God is
> buried; you shall lay my bones beside his bones. 1 Ki 13.30-31
It's a sad, beautiful story about the pain of the divorce between Judah and Israel that shouldn't be marred by tiresome religious finger-wagging.
## Rabbinical commentaries on the Old Prophet
Interestingly, Rashi and the rest of the rabbinic tradition -- never ones to miss an opportunity at religious finger-wagging -- insist (with no textual basis) that the Old Prophet is a *false* prophet, and so this passage has been targummed.
1 Ki 13.11 targum[2]:
> And one old *lying* prophet was dwelling in Bethel,
That then creates a problem as to how to explain the old prophet prophesying and why the Spirit of God would come upon him. This is explained by the power of a good meal. The meal was so *refreshing* that it even allowed a false prophet to give a true prophecy!
> From here they [the Rabbis] deduced that [offering] refreshment is a
> great thing, for it causes the Divine Presence to rest on the prophets
> of the Baal.[1]
But the old prophet was not a prophet of Baal, he was a prophet of YHWH who happened to live in a city that used to be a site honored by YWHW and by Jacob, but now was divorced from YHWH due to the political bumbling of Rehoboam and Jeroboam, and the spiritual and social fallout of this separation is the topic of 1 Kings 12-13.
It is a good idea to avoid reading facile moral stories into every tale of loss in the Bible.
[1] Rashi Commentaries on 1 Ki 13.20
[2]Cathcart, K., Maher, M., & McNamara, M. (Eds.). (1990). The Aramaic Bible: Targum Jonathan of the Former Prophets. (D. J. Harrington & A. J. Saldarini, Trans.) (Vol. 10, 1 Ki 13:11). Collegeville, MN: The Liturgical Press.