Sahih al-Bukhari Book 67, Hadith 165
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.
I will narrate to you a Habith I heard from Allah's Messenger (ﷺ) and none other than I will tell you of it. I heard Allah's Messenger (ﷺ) saying, "From among the portents of the Hour are the following: Religious knowledge will be taken away; General ignorance (in religious matters) will increase; illegal Sexual intercourse will prevail: Drinking of alcoholic drinks will prevail. Men will decrease in number, and women will increase in number, so much so that fifty women will be looked after by one man."
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 Allah's Messenger (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."