وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ
قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مَنْ أَفْطَرَ يَوْمًا مِنْ رَمَضَانَ مِنْ غَيْرِ رُخْصَةٍ وَلَا مَرَضٍ لَمْ يَقْضِ عَنْهُ صَوْمُ الدَّهْرِ كُلِّهِ وَإِنْ صَامَهُ»
Abu Hurayrah reported God’s messenger as saying, “If anyone breaks his fast one day in Ramadan without a concession* or without being ill, a perpetual fast will not atone for it even if he observes it.” *e.g. while travelling. Ahmad, Tirmidhi, Abu Dawud, Ibn Majah, Darimi and Bukhari in a chapter heading transmitted it. Tirmidhi said that he heard Muhammad, i.e. Bukhari, say this was the only tradition he knew by Abul Mutawwis the transmitter.
Mishkat al-Masabih 1923, Book 8, Fasting, Hadith 57. 1 min read