Sahih Bukhari Volume 008, Book 073, Hadith Number 004.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 73. Good Manners and Form (Al-Adab)
Narated By 'Abdullah bin â€˜Amr: Allah's Apostle said. "It is one of the greatest sins that a man should curse his parents." It was asked (by the people), "O Allah's Apostle! How does a man curse his parents?" The Prophet said, "'The man abuses the father of another man and the latter abuses the father of the former and abuses his mother."