The Book of Fasting
13/14. Chapter:
The strict prohibition of intercourse during the day in Ramadan for one who is fasting; And the obligation of offering major expiation and the definition thereof; And that it is obligatory for both the one who can afford it and the one who cannot afford it, and it remains an obligation for the one who cannot afford it until he has the means
Sahih Muslim
وَحَدَّثَنَا مُحَمَّدُ بْنُ رَافِعٍ، حَدَّثَنَا إِسْحَاقُ بْنُ عِيسَى، أَخْبَرَنَا مَالِكٌ، عَنِ الزُّهْرِيِّ، بِهَذَا الإِسْنَادِ أَنَّ رَجُلاً، أَفْطَرَ فِي رَمَضَانَ فَأَمَرَهُ رَسُولُ اللَّهِ صلى الله عليه وسلم أَنْ يُكَفِّرَ بِعِتْقِ رَقَبَةٍ . ثُمَّ ذَكَرَ بِمِثْلِ حَدِيثِ ابْنِ عُيَيْنَةَ .
This hadith has been narrated on the authority of Zuhri with the same chain of transmitters that a person broke fast in Ramadan whereupon the Messenger of Allah (ﷺ) commanded him to free a slave (as an atonement), and the rest of the hadith is the same as narrated by Ibn Uyaina.
Reference : Sahih Muslim 1111dIn-book reference : Book 13, Hadith 104USC-MSA web (English) reference : Book 6, Hadith 2460