Narrated Ibn Abi Nu'm: A person asked `Abdullah bin `Umar whether a Muslim could kill flies. I heard him saying (in reply). "The people of Iraq are asking about the killing of flies while they themselves murdered the son of the daughter of Allah's Apostle . The Prophet said, They (i.e. Hasan and Husain) are my two sweet basils in this world."

Narrated Ibn Abi Na'm: I was present when a man asked Ibn `Umar about the blood of mosquitoes. Ibn `Umar said, "From where are you?" The man replied. "From Iraq." Ibn `Umar said, "Look at that! he is asking me about the blood of Mosquitoes while they (the Iraqis) have killed the (grand) son of the Prophet. I have heard the Prophet saying, "They (Hasan and Husain) are my two sweet-smelling flowers in this world."