What does Judges 9:15 mean?
Jotham's fable (Judges 9:7–14) has followed an imaginary search committee: trees looking for a king. They have asked the olive tree, the fig tree, and the grapevine to rule over them. All three said no. These plants valued what they were producing too much to stop and command other trees. Since they were capable, productive, and worthwhile, they had no drive to seek power over others. That changes when the trees turn to a different kind of plant: the bramble."Brambles" depicted in this passage are plants modern English speakers might call "pricker bushes" or simply "thornbushes." Middle eastern versions tend to have thin, woody stems producing hard spikes. These were most often considered weeds. Worse, they become a fire hazard. Dead brambles are natural tinder. In the context of this parable, the only thing a bramble can offer is pain and destruction—so it has every reason to be power-hungry and seek dominance over others.
For this reason, the bramble seems surprised by the offer, questioning if the other trees are coming "in good faith," meaning with sincerity and honesty. The bramble replies with a condition for its leadership. If the other trees anoint it as king "in good faith," they are welcome to take refuge under its protection. This, itself, is ironic, since a bramble produces almost no shade, does not have strong limbs, and has sharp thorns. If the other trees are not acting with good intent, the bramble promises to send out fire to devour all other trees.
The bramble's threat mentions the "cedars of Lebanon," a common metaphor for something strong and valuable. In modern English, an equivalent phrase might be "the mighty oaks."
Jotham delivers this fable as his murderous brother, Abimelech, is being anointed king (Judges 9:1–6). The takeaway seems simple: a bramble would not make a particularly good king over the trees, even if it was the only one willing to take the job. In fact, that decision carries far more risk than reward. The same applies to Shechem's choice of Abimelech. Jotham will add that meaning to the story in the following verses.