Among the sections dealing with supererogatory acts he says: “Al-Bayhaqī transmits with his chain that Abū Dharr—may Allah be pleased with him—performed a large number of units of prayer. When he finished, al-Aḥnaf ibn Qays asked him, ‘Do you know whether you ended on an even number or on an odd?’ He replied: … ‘I heard my intimate friend Abū’l-Qāsim ﷺ say: ‘No servant prostrates to Allah a single prostration without Allah raising him one degree by it and erasing from him one sin.’” Al-Dārimī recorded it in his Musnad with a sound chain, save for one man whose reliability is disputed.”

I say: If only the compiler—may Allah preserve him—had remained silent concerning al-Dārimī’s chain after attributing the report to al-Bayhaqī, for al-Dārimī’s isnād is sound and does not contain the narrator in question; Aḥmad likewise recorded it.

I have traced the ḥadith, together with supporting narrations, in Irwāʾ al-Ghalīl, no. 457.