It wasnarrated from Muhammad bin Ibrahim that Usamah bin Zaid usedto fastthe sacred months. The Messenger of Allah (ﷺ) said to him:
"FastShawwal." So he forsook the sacred months and he continued tofastShawwal until he died. (JA)
English reference (JA): Vol. 1, Book 7, Hadith 1744 (JA)
Arabic reference (JA): Book 7, Hadith 1816 (JA)