Sahih al-Bukhari 5232
Sahih al-Bukhari · Book 67: Wedlock, Marriage (Nikaah) · A man should not stay with a woman in seclusion
Narrated `Uqba bin 'Amir:
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ ، حَدَّثَنَا لَيْثٌ ، عَنْ يَزِيدَ بْنِ أَبِي حَبِيبٍ ، عَنْ أَبِي الْخَيْرِ ، عَنْ عُقْبَةَ بْنِ عَامِرٍ ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِيَّاكُمْ وَالدُّخُولَ عَلَى النِّسَاءِ ". فَقَالَ رَجُلٌ مِنَ الأَنْصَارِ يَا رَسُولَ اللَّهِ أَفَرَأَيْتَ الْحَمْوَ. قَالَ " الْحَمْوُ الْمَوْتُ " .
Allah's Messenger (ﷺ) said, "Beware of entering upon the ladies." A man from the Ansar said, "Allah's Apostle! What about Al-Hamu the in-laws of the wife (the brothers of her husband or his nephews etc.)?" The Prophet (ﷺ) replied: The in-laws of the wife are death itself.