Hadith 5:115
Abu Huraira reported God’s messenger as saying, “There is zakat applicable to everything, and the zakat of the body is fasting.” Ibn Majah transmitted it.
وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «لِكُلِّ شَيْءٍ زَكَاةٌ وَزَكَاةُ الْجَسَدِ الصَّوْمُ» . رَوَاهُ ابْن مَاجَه
Original Reference: Mishkat al-Masabih 2072