Sayyiduna Subayh (may Allah be pleased with him) narrated: I was at the door of the Prophet (peace and blessings be upon him) when Sayyiduna Ali (may Allah be pleased with him), Sayyidah Fatimah (may Allah be pleased with her), Sayyiduna Hasan (may Allah be pleased with him) and Sayyiduna Husayn (may Allah be pleased with him) came, and they sat down in a corner. The Prophet (peace and blessings be upon him) came out and said: You are upon goodness. The narrator said: At that time the Prophet (peace and blessings be upon him) had a Khaybari cloak on him; he put that cloak over them and said: "I will fight against whoever fights against you, and I will be at peace with whoever is at peace with you."
Al-Tabarani recorded it in al-Mu'jam al-Awsat, and its chain contains narrators whom I do not know.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب المناقب / 14989