Abū Ja'far Muḥammad ibn 'Alī ibn Nu'mān (Arabic: ابوجعفر محمّد بن علي بن نعمان ), known as Mu'min al-Ṭāq (مؤمن الطاق) was a distinguished theologist and a devoted follower of Muhammad al-Baqir and Ja'far al-Sadiq, whose debates about imamate are famous.
To refute abu-Hanifa, the Shias gave him the nickname Mu'min al-Taq (lit.The True Believer of the Gateway).
The heresiographers refer to his circle as AnNu'maniya, and he differentiated himself from the rest of Ja'far al-Sadiq's followers via his mastery of dialectics, his theological knowledge, and the sharpness of his rejoinders in debates with his opponents.
Al-Ahwal, a fervent Shi'i, was initially one of the most dedicated followers of al-Baqir, whose claims he defended against Zayd.
Dissociation (bara'a),then, is a luxury which the Imams can ill afford, even if Mu'min al-Taq, Zurara, and their ilk deserve it in principle.
Al-Dahhak was happy at that and regarded it as a victory for him, so he said to his companions: "Certainly, if this (Mu'min al-Taq) enter (a debate) with you, he will benefit you."