1. Al-Mutawakkil had a Christian clerk who was preferable by him. Because he loved him too much he surnamed him as Abu Noah. Some other clerks denied that and said that it was not permissible to surname an unbeliever. Al-Mutawakkil asked the jurisprudents to give him a fatwa on that but they did not agree on one fatwa. Some of them said it was permissible and others said it was not. He sent the question to Imam al-Hadi (a.s.) who wrote to him with this answer, (Perdition overtake both hands of Abu Lahab, and he will perish). This answer was the most wonderful answer in the field of fatwas. Imam al-Hadi (a.s.) quoted this Qur’anic verse that declared the permissibility of surnaming the unbelievers. Al-Mutawakkil followed this fatwa of Imam al-Hadi (a.s.).
2. Once, al-Mutawakkil became ill and he vowed that if Allah healed him, he would pay many dinars as charity. When he restored to health, he gathered the jurisprudents and asked them about the amount of the money he should pay as charity to fulfill his vow, but they disagreed on that. Then, he asked Imam al-Hadi (a.s.) about that. Imam al-Hadi (a.s.) said that al-Mutawakkil had to pay eighty-three dinars. The jurisprudents were astonished at that and asked al-Mutawakkil, ‘Where from did he get this answer?’ Al-Mutawakkil wrote to Imam al-Hadi (a.s.) asking him about the source of his answer, and Imam al-Hadi (a.s.) replied, ‘Allah the Almighty says, (ِAllah has given you victory in many battlefields). All our ancestors narrated that the battlefields were eighty-three.’ He said in the end of the answer, ‘Whatever more good Ameerul Mo’minin does shall be more useful and rewardable to him in this life and in the afterlife.’
3. One day, a Christian man, who had committed adultery with a Muslim woman, was brought before al-Mutawakkil. When al-Mutawakkil wanted to execute the legal penalty on the Christian, he turned Muslim. Yahya bin Aktham said, ‘His faith (in Islam) cancelled his polytheism and sin.’ Another jurisprudent said, ‘He is subjected to three punishments (by the whip).’ Other jurisprudents said different things. Al-Mutawakkil asked his men to take a fatwa from Imam al-Hadi (a.s.) about this matter. Imam al-Hadi (a.s.) replied, ‘He should be whipped until he dies.’ Yahya and the other jurisprudents denied this fatwa of Imam al-Hadi (a.s.) and said that he took this fatwa neither from the Book nor from the Sunna. Al-Mutawakkil wrote to Imam al-Hadi (a.s.) saying, ‘The jurisprudents of Muslims denied this fatwa and said that neither the Book nor the Sunna had said so. Would you please show us why you have imposed on him the whipping until he would die?’
Imam al-Hadi (a.s.) replied by quoting this Qur’anic verse, (But when they saw Our punishment, they said: We believe in Allah alone and we deny what we used to associate with Him. But their belief was not going to profit them when they had seen Our punishment). Al-Mutawakkil took the fatwa of Imam al-Hadi (a.s.) and ordered the man to be whipped until he died.’
Reference : The Life of Imam ALI bin Muhammad AL-HADI