Check meaning, particle and ending together.
1. The sentence prevents an action: “do not” or “let ... not.”
2. Prohibitive لَا comes before an imperfect verb.
3. The imperfect verb is jussive: sukun, removal of inflectional nūn, or another already established jussive form.
A negative statement with لَا is not automatically a prohibition. Ask whether the speaker is reporting non-occurrence or preventing an action.