Sunan Abi Dawud

Narrated Aisha, Ummul Mu'minin: The Messenger of Allah (ﷺ) used to setup a pulpit in the mosque for Hassan who would stand on it and satirise those who spoke against the Messenger of Allah (ﷺ). The Messenger of Allah (ﷺ) would say: The spirit of holiness (i.e. Gabriel) is with Hassan so long as he speaks in defence of the Messenger of Allah (ﷺ)