I asked Sa'd b. Abu Waqqas (Allah be pleased with him) about Mut'a, whereupon he said: We did that, and it was the day when he was an unbeliever living in (one of the) houses of Mecca.
فَعَلْنَاهَا وَهَذَا يَوْمَئِذٍ كَافِرٌ بِالْعُرُشِ يَعْنِي بُيُوتَ مَكَّةَ