Imam al-Hadi (a.s.) talked to his companions about some important Islamic events that happened at the first Islamic age. One of them was the killing of the martyr Qanbar, Imam Ali’s servant, at the hand of the tyrant al-Hajjaj bin Yousuf ath-Thaqafi. He said,
‘Qanbar came in to al-Hajjaj bin Yousuf who shouted at him, ‘What service did you offer to Ali bin Abu Talib?’
Qanbar said, ‘I helped him in performing ablution.’
Al-Hajjaj said, ‘What did he say when he finished his ablution?’
Qanbar said, ‘He recited this Qur’anic verse: (But when they neglected that with which they had been admonished, We opened for them the doors of all things, until when they rejoiced in what they were given We seized them suddenly; then lo! they were in utter despair. So the roots of the people who were unjust were cut off; and all praise is due to Allah, the Lord of the worlds).
Al-Hajjaj said, ‘I think he meant us?!’
Qanbar said, ‘Yes, he did.’
Al-Hajjaj said to Qanbar, ‘What do you do if I behead you?’
Qanbar said, ‘Then I shall be happy and you shall be wretched.’
The tyrant ordered his men to behead this good man and he was killed.’( Rijal al-Kashshi.)
Reference : The Life of Imam ALI bin Muhammad AL-HADI