What is the ruling of the Ahl al-Sunnah wa al-Jama'ah concerning one who publicly curses and insults a member of the Prophet's household (peace and blessings be upon him) from the lineage of Fatimah al-Zahra?

It is forbidden to curse a Muslim, and this prohibition is particularly emphasized regarding the household of the Prophet (peace and blessings be upon him), due to Allah's saying: "Say, 'I ask not of you any reward for it save love of kin.'" Cursing them harms the Messenger of Allah (peace and blessings be upon him), and harming him is forbidden by Islamic law, due to Allah's saying: "Indeed, those who abuse Allah and His Messenger—Allah has cursed them in this world and the Hereafter and prepared for them a humiliating punishment."