Particular prohibited matters (1) cannot be individually stipulated in a text, whether by the Messenger of Allah or by an Imam. Rather, they necessarily require ijtihād, and the one exercising ijtihād will sometimes be correct and sometimes err.

As the Prophet—may Allah bless him and grant him peace—said:

“When a judge exercises ijtihād and reaches the correct decision, he receives two rewards; if he errs, he receives one reward.” (2)

Likewise, he said to Saʿd (3) ibn Muʿādh—who was serving as arbiter in a particular case in which the arbiter is required to choose the most appropriate course—after he ruled that the combatants of Banū Qurayza were to be killed and their women and children taken captive:

“You have indeed judged them according to Allah’s judgment from above the seven heavens.” (4)

He would also say to anyone whom he dispatched as commander of an expedition or an army:

“When you lay siege to the inhabitants of a fortress and they ask you to accept their surrender according to Allah’s judgment, you do not know what Allah’s judgment concerning them is. Rather, accept their surrender according to your judgment and that of your companions.” (5)

All three hadiths are established in authentic collections.

It thus becomes clear that every benefit served by an Imam’s infallibility is already secured by the Messenger’s infallibility. To Allah belong all praise and favor. Experience confirms this. We have observed that the closer people are to following the Sunnah and the hadith and to following the Companions, the more complete their welfare is in this world and in their religion; and the further they are from this, the more the opposite is true.

And because the Shiʿah are the people furthest from following the infallible one—there being no doubt concerning