Sayyiduna Abu Bakrah (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him) saying: "This son of mine is a leader (meaning Sayyiduna al-Hasan bin Ali, may Allah be pleased with them both), and perhaps two groups of Muslims will be reconciled through him."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13389
Sayyiduna Ali (may Allah be pleased with him) said: When Hasan (may Allah be pleased with him) was born, I named him Harb. The Prophet (peace and blessings be upon him) said: "What have you named my son?" I said: Harb. He (peace and blessings be upon him) said: "No, rather he is Hasan." When Husayn (may Allah be pleased with him) was born, he (peace and blessings be upon him) asked: "What is his name?" I said: Harb. He (peace and blessings be upon him) said: "No, he is Husayn."
Then when Muhsin was born, he (peace and blessings be upon him) said: "What is my son's name?" I said: Harb. He (peace and blessings be upon him) said: "No, rather he is Muhsin." Then the Prophet (peace and blessings be upon him) said: "I have named these sons of mine after the sons of Harun (peace be upon him): Shabbar, Shabbir and Mushabbir."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13390
Sa'd (may Allah be pleased with him) said: Revelation came down upon the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) brought Ali, Fatimah, Hasan and Husayn (may Allah be pleased with them) under his garment and said: "O Allah, these are my family and my household (Ahl al-Bayt)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13391
Sayyiduna Sa'd (may Allah be pleased with him) said: When this verse was revealed to the Prophet (peace and blessings be upon him): "Let us call our sons and your sons, our women and your women" [Surah Al Imran: 61], he (peace and blessings be upon him) called Ali, Fatimah, Hasan and Husayn (may Allah be pleased with them) and said: "O Allah, these are my family."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13392