Ibn Aqil Hanbali and his repentance from mutazili and Sufism.
Ibn Rajab Hanbali said that Ibn Aqil said
واعتقدت في الحلاج أنه من أهل الدین والزهد والكرامات. ونصرت ذلك في جزء عملته. وأنا تائب إلى الله تعالى منه، وأنه قتل بإجماع علماء عصره، وأصابوا في ذلك، وأخطأ هو. ومع ذلك فإني أستغفر الله تعالى، وأتوب إليه من مخالطة المعتزلة، والمبتدعة، وغير ذلك، والترحم عليهم، والتعظيم لهم فإن ذلك كله حرام. ولا يحل لمسلم فعله
I had a belief that Husayn bin Munsur Hallaaj (the extreme Sufi) was among the ahlul Deen and the righteous. And that he had miracles, I also wrote in his defence.
I ask forgiveness from all of this before Allah. He was killed by the consensus of scholars. The scholars did the right thing as he was wrong. I ask Allah’s forgiveness regarding him that May Allah forgive me. I ask forgiveness that I was with the Mutazila and people of innovation etc and that I used to pray for mercy and venerate them. It is prohibited and not allowed for any Muslim (i.e. to Praise hallaj and people of innovations).
(ذیل طبقات الحنابلة، ۱/۳۲۳)