finds that his faith is diminished—either a diminution in its obligatory completeness or a shortfall in its recommended perfection—yet he is not rendered an unbeliever on that account.

What, then, is the evidence that faith both increases and decreases?

As for the evidence of increase, Allah the Exalted says: “The true believers are only those who, when Allah is mentioned, their hearts tremble; and when His verses are recited to them, it increases them in faith” (Qur’an 8:2). This shows that faith grows through listening to the Quran. He also says: “Whenever a surah is sent down, some of them say, ‘Which of you has this increased in faith?’ As for those who believe, it increases them in faith, and they rejoice” (Qur’an 9:124). This proves that revelation, its recitation, and reflection upon it augment faith. Likewise, the Almighty says: “We have appointed none but angels as keepers of the Fire, and We have fixed their number only as a trial for those who disbelieve, so that the People of the Book may be certain, and the believers may increase in faith” (Qur’an 74:31). Thus, faith rises through acts of obedience and through firm assent.

As for decrease: everything that is capable of increase is, by that very fact, capable of decrease. That is one angle of proof. It is also affirmed by the authentic hadith in which the Prophet ﷺ said: “On the Day of Resurrection Allah—glorified and exalted—is He—will say, ‘Bring out of the Fire anyone who had…’”