In the song, Meroz is cursed because its inhabitants did not come to help in the battle, described as not helping the LORD against the mighty (Judges 5:23). The curse is spoken by the angel of the LORD within the song (Judges 5:23).
In Judges 5:23–27 the song pronounces a sharp contrast. Meroz is called down with a curse because its people did not show up to help in the battle, described as helping Yahweh in the fight against powerful enemies. This passage sits inside the victory song of Deborah and Barak in Judges 5, which retells the events narrated in Judges 4 in poetic form. The song moves between praise, memory of the battle, and evaluation of different groups’ responses.
This section of the song draws a deliberate contrast: one community is condemned for staying out of a life‑and‑death conflict, and one woman is praised for ending the enemy commander’s threat. The text is explicit that Meroz is cursed because it “didn’t come to the help of Yahweh … against the mighty” (verse 23).
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with Judges 5:23, then read the surrounding section so the answer stays connected to the passage's flow.
23Curse you Meroz, said the angel of Yahweh. Curse you bitterly the inhabitants of it, Because they didn`t come to the help of Yahweh, To the help of Yahweh against the mighty.