Twelfth Principle: Refraining from acting upon a weak ḥadith in matters of devotional merits

It has become widespread among many scholars and their students that a weak ḥadith may be put into practice when it concerns the virtues of deeds, and they imagine that no one disagrees with this. After all, al-Nawawi—may Allah have mercy on him—reported a consensus to that effect in more than one of his works. What he transmitted, however, is open to serious scrutiny, for the disagreement on this point is well-known: a number of rigorous scholars maintain that a weak ḥadith is not to be acted upon at all, whether in legal rulings or in supererogatory virtues. Shaykh al-Qasimi—may Allah have mercy on him—says in Qawāʿid al-Taḥdīth, p. 94:

“Ibn Sayyid al-Nas related this view in ʿUyūn al-Athar from Yaḥyā ibn Maʿīn, and Fath al-Mughīth ascribes it to Abū Bakr ibn al-ʿArabī. It appears that al-Bukhārī and Muslim held the same opinion as well … and it is also the position of Ibn Ḥazm.”

I say: This, beyond any doubt, is the correct view in my estimation for several reasons:

First: A weak ḥadith yields only a doubtful, indeed predominately unlikely, presumption, and by unanimous agreement acting on such a presumption is impermissible. Whoever makes an exception by allowing the use of a weak ḥadith in the virtues of deeds