«إِنْ دَخَلْتَ الدَّارَ فَأَنْتَ حُرٌّ»
If you enter the house, you are free.
Dakhala is morphologically past and anta hurr is a nominal sentence. Yet the entering is contemplated as a future condition; the speaker stipulates an outcome tied to its occurrence.
The utterance does not merely report a past entry nor prove that freedom is already effective independently of the condition. The situation before and after fulfillment differs. The crucial distinction is past verbal form versus the temporal force of the condition.