Sahih Bukhari

Narrated `Uqba bin 'Amir: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