Al-Adab Al-Mufrad Hadith 731

Abu Naufal bin Abu Aqrab has narrated on the authority of his father that he asked the Prophet (ﷺ) about (voluntary) fasts. He said,"observe one fast every month." He submitted, "May my father and mother be ransomed to you, permit me to keep more. "The Prophet (ﷺ) repeated (in anger) what he had said, "permit me to keep more, permit me to keep more.” He then added," keep two fasts every month". But, Abu Nawafal’s father again requested, "May my parents be ransomed to you, allow me to keep more because I find myself able (to observe more), I find myself able, I find myself able." He then maintained silence and it seemed that he would not give permission any more until he said," keep three fasts every month."