صحيح البخاري

Narrated Ibn Abi Nu'm:

`Abdullah bin `Umar was asked about a muhrim (a person in the state of pilgrimage). Shu'bah (a subnarrator) said "I think killing flies."

I heard him saying (in reply). "The people of Iraq are asking about flies while they themselves murdered the son of the daughter of Allah's Messenger. The Prophet (ﷺ) said, 'They (i.e. Hasan and Husain) are my two sweet basils in this world.' "