From Sahih Muslim (Hadith 6261):
A'isha reported that Allah's Apostle (ﷺ) went out one norning wearing a striped cloak of the black camel's hair that there came Hasan b. 'Ali. He wrapped hitn under it, then came Husain and he wrapped him under it along with the other one (Hasan). Then came Fatima and he took her under it, then came 'Ali and he also took him under it and then said:Allah only desires to take away any uncleanliness from you, O people of the household, and purify you (thorough purifying)
Reference: Muslim 6261