«إن من أكبر الكبائر أن يلعن الرجل والديه: يلعن أبا الرجل فيلعن أباه ويلعن أمه فيلعن أمه»
The Prophet (peace and blessings be upon him) said:
"Indeed, among the gravest of sins is that a man curses his own parents. (When the Companions asked, he (peace and blessings be upon him) said: It happens like this:) he abuses another man's father, so that man in return abuses his father; and he abuses his mother, so that man in return abuses his mother."
Hadith Referenceصحیح الجامع الصغیر / حرف الألف / 2214