أَعَصَيْتَ رَبَّكَ / أَتَعْصِي رَبَّكَ
Did you disobey your Lord? / Would you disobey your Lord?
The past-tense form can rebuke a completed act: it should not have occurred. A future-oriented form can warn against an act yet to occur: it ought not to be done.
The source uses the notion of mā kāna yanbaghī—something unfitting or impermissible. The distinction is controlled by temporal reference and context, not simply by a mechanical reading of verb morphology.
ContextFunctionImplied meaning
Known past wrongRebukeIt should not have happened
Prospective wrongProhibition/denialDo not do that
Unknown occurrenceGenuine questionDid it take place?