بُلُوغُ الْمَرَامِ
Bulugh al-Maram 681
Fasting
وَعَنْ أَبِي أَيُّوبَ اَلْأَنْصَارِيِّ - رضى الله عنه - أَنَّ رَسُولَ اَللَّهِ - صلى الله عليه وسلم -قَالَ: { مَنْ صَامَ رَمَضَانَ, ثُمَّ أَتْبَعَهُ سِتًّا مِنْ شَوَّالٍ كَانَ كَصِيَامِ اَلدَّهْرِ } رَوَاهُ مُسْلِمٌ [1] .
Abu Aiyub Al-Ansari (RAA) narrated that The Messenger of Allah (ﷺ) said: "Whoever fasts during the month of Ramadan and then follows it with six days of Shawwal will be (rewarded) as if he had fasted the entire year." Related by Muslim.
Arabic/English book reference: Book 5, Hadith 701