General Behavior (Kitab Al-Adab)
Dawud :: Book 41 : Hadith 4997
Narrated Aisha, Ummul Mu'minin:
The Apostle of Allah (peace_be_upon_him) used to setup a pulpit in the mosque for Hassan who would stand on it and satirise those who spoke against the Apostle of Allah (peace_be_upon_him). The Apostle of Allah (peace_be_upon_him) would say: The spirit of holiness (i.e. Gabriel) is with Hassan so long as he speaks in defence of the Apostle of Allah (peace_be_upon_him).