صَحِيحُ مُسْلِمٍ
Sahih Muslim 1146 c
The Book of Fasting
It is Permissible to delay making up missed Ramadan Fasts until before the next Ramadan comes, and this is for those who broke the fast for a reason such as sickness, travel, menstruation and the like
وَحَدَّثَنِيهِ مُحَمَّدُ بْنُ رَافِعٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا ابْنُ جُرَيْجٍ، حَدَّثَنِي يَحْيَى، بْنُ سَعِيدٍ بِهَذَا الإِسْنَادِ وَقَالَ فَظَنَنْتُ أَنَّ ذَلِكَ لِمَكَانِهَا مِنَ النَّبِيِّ صلى الله عليه وسلم . يَحْيَى يَقُولُهُ .
In another version of the previous hadith, the words are: " Yahya said: I think it was due to the regard for the Messenger of Allah (ﷺ)."
Sahih Muslim, 1146 cSahihصحيح