al-Ja‘d ibn Dirham, Ghaylān al-Qadarī, and others—that would serve the common good, unlike leaving him free to call others to his innovation when he refuses to accept the truth, whether because of his desires or his impaired understanding. Addressing him brings nothing but harm and detriment to him and to the Muslims.

The Muslims established the proof against Ghaylān and others like him, debated with him, and explained the truth to him, as ‘Umar ibn ‘Abd al-‘Azīz, may Allah be pleased with him, did when he called upon him to repent. He subsequently broke his pledge of repentance, so they put him to death.

Likewise, ‘Alī, may Allah be pleased with him, sent Ibn ‘Abbās to the Khawārij, and he debated with them. Half of them then recanted, and ‘Alī subsequently fought those who remained.

The point is that when the truth has become manifest and known, and the person calling others to innovation intends to harm people, he is met with punishment. Allah Most High says:

“As for those who dispute concerning Allah after He has been acknowledged, their argument is invalid before their Lord. Wrath is upon them, and theirs will be a severe punishment.” [al-Shūrā: 16]

They may forbid argument and debate when the disputant has insufficient knowledge of the proofs and of how to answer doubts, out of fear that the person leading others astray might corrupt him. This is like forbidding someone weak in combat from fighting a powerful, burly fighter among the unbelievers, since that would harm him and the Muslims without bringing any benefit. They may also forbid debate if the disputant is