It is narrated from Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) that when revelation came down upon the Messenger of Allah (peace and blessings be upon him), he (peace and blessings be upon him) took Sayyiduna Ali and Sayyidah Fatimah (may Allah be pleased with them both) and their two sons under his sheet, and then supplicated: 'Allahumma ha'ula'i ahli wa ahlu bayti' (O Allah! These are my own family and my Ahl al-Bayt).

It is narrated from Sayyiduna Abdullah bin Ja'far (may Allah be pleased with him) that he said: When the Messenger of Allah (peace and blessings be upon him) saw mercy descending, he (peace and blessings be upon him) said: "Call them to me, call them to me." Sayyidah Safiyyah (may Allah be pleased with her) asked: O Messenger of Allah! Whom shall I call? He (peace and blessings be upon him) said: "My Ahl al-Bayt, that is, Ali, Fatimah, al-Hasan and al-Husayn." So she brought them. Then the Prophet (peace and blessings be upon him) placed his cloak over them, then raised his hands and supplicated: 'Allahumma ha'ula'i ali, fa-salli ala Muhammadin wa ala ali Muhammad' (O Allah! These are my family (al), so send Your blessings upon Muhammad and upon the family of Muhammad). And Allah, the Mighty and Majestic, revealed this verse: "Allah only intends to remove impurity from you, O household of the Prophet, and to purify you thoroughly." [Surah al-Ahzab: 33] This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it; while it is established as authentic, on the condition of Imam Bukhari and Imam Muslim, that he (peace and blessings be upon him) taught the Companions to send blessings upon his Ahl al-Bayt just as he taught them to send blessings upon his family (al).