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
حَدَّثَنِي مُحَمَّدُ بْنُ رَافِعٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا ابْنُ جُرَيْجٍ، حَدَّثَنِي ابْنُ شِهَابٍ، عَنْ حُمَيْدِ بْنِ عَبْدِ الرَّحْمَنِ، أَنَّ أَبَا هُرَيْرَةَ، حَدَّثَهُ أَنَّ النَّبِيَّ صلى الله عليه وسلم أَمَرَ رَجُلاً أَفْطَرَ فِي رَمَضَانَ أَنْ يُعْتِقَ رَقَبَةً أَوْ يَصُومَ شَهْرَيْنِ أَوْ يُطْعِمَ سِتِّينَ مِسْكِينًا .
Humaid b. 'Abd al-Rahman reported that Abu Huraira had narrated to him that the Messenger of Allah (ﷺ) commanded the person (who) broke the fast in Ramadan to free a slave or observe fasts for two (consecutive) months or feed sixty poor persons.
Reference : Sahih Muslim 1111eIn-book reference : Book 13, Hadith 105USC-MSA web (English) reference : Book 6, Hadith 2461