He—may Allah have mercy on him—was asked about a man who said of Alī ibn Abī Tālib—may Allah be pleased with him—that he was not a member of the Prophet’s household, that invoking blessings upon him was impermissible, and that doing so was a religious innovation.
He replied:
There is no disagreement among Muslims that Alī ibn Abī Tālib belongs to the Prophet’s household. This is so evident to Muslims that it requires no proof. Indeed, after the Prophet, may Allah bless him and grant him peace, he is the best member of the household and the best of Banū Hāshim. It is authentically established that the Prophet, may Allah bless him and grant him peace, wrapped his cloak around Alī, Fātimah, Hasan, and Husayn, saying:
“O Allah, these are the members of my household. Remove impurity from them and purify them thoroughly.”
As for invoking blessings upon him individually, this depends on whether blessings may be invoked individually upon someone other than the Prophet, may Allah bless him and grant him peace—for example, by saying, “O Allah, bless Umar,” or “O Allah, bless Alī.” Scholars have differed on this matter.
Mālik, al-Shāfiʿī, and a group of Hanbalī scholars held that blessings should not be invoked individually upon anyone other than the Prophet, may Allah bless him and grant him peace. This accords with the report that Ibn Abbās said: “I do not know of anyone upon whom it is fitting to invoke blessings except the Prophet, may Allah bless him and grant him peace.”