Among the major sins, is for a person to abuse his parents

The Prophet (p) said a person would indirectly be abusing his or her own parents. He said, “Among the major sins, is for a person to abuse his parents”. A companion said, ‘How would a man abuse (his parents)? the Prophet (p) said, “(It would be) by him abusing someone, who will then (in return) abuse his parents.

Imamal-Bukhari,Adab al-Mufrad, hadith no. 27