Abdullah bin Amr (may Allah be pleased with him) reports that the Messenger of Allah (peace and blessings be upon him) said: "A man's reviling his parents is a major sin." The Companions asked, "O Messenger of Allah! Does a man revile his own parents?" He (peace and blessings be upon him) replied: "Yes, he abuses another man's father, so (in return) that man abuses his father, and he abuses another man's mother, so (in return) that man abuses his mother." Agreed upon.