Messenger of Allah 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.  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ إِيَّاكُمْ وَالدُّخُولَ عَلَى النِّسَاءِ فَقَالَ رَجُلٌ مِنَ الأَنْصَارِ يَا رَسُولَ اللَّهِ أَفَرَأَيْتَ الْحَمْوَ قَالَ الْحَمْوُ الْمَوْتُ  

The Prophet ﷺ said, "No man should stay with a lady in seclusion except in the presence of a Dhu- Muhram." A man stood up and said, "O Messenger of Allah ﷺ! My wife has gone out intending to perform the Hajj and I have been enrolled (in the army) for such-and-such campaign." The Prophet ﷺ said, "Return and perform the Hajj with your wife."  

عَنِ النَّبِيِّ ﷺ قَالَ لاَ يَخْلُوَنَّ رَجُلٌ بِامْرَأَةٍ إِلاَّ مَعَ ذِي مَحْرَمٍ فَقَامَ رَجُلٌ فَقَالَ يَا رَسُولَ اللَّهِ امْرَأَتِي خَرَجَتْ حَاجَّةً وَاكْتُتِبْتُ فِي غَزْوَةِ كَذَا وَكَذَا قَالَ ارْجِعْ فَحُجَّ مَعَ امْرَأَتِكَ