The Book of Fasting
13/13. Chapter:
The fasting is valid for the one who is Junub when dawn comes
Sahih Muslim
وَحَدَّثَنِي حَرْمَلَةُ بْنُ يَحْيَى، أَخْبَرَنَا ابْنُ وَهْبٍ، أَخْبَرَنِي يُونُسُ، عَنِ ابْنِ شِهَابٍ، عَنْ عُرْوَةَ بْنِ الزُّبَيْرِ، وَأَبِي، بَكْرِ بْنِ عَبْدِ الرَّحْمَنِ أَنَّ عَائِشَةَ، زَوْجَ النَّبِيِّ صلى الله عليه وسلم قَالَتْ قَدْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يُدْرِكُهُ الْفَجْرُ فِي رَمَضَانَ وَهُوَ جُنُبٌ مِنْ غَيْرِ حُلُمٍ فَيَغْتَسِلُ وَيَصُومُ .
'A'isha, the wife of the Messenger of Allah (ﷺ), said: The dawn broke upon the Messenger of Allah (ﷺ) during the Ramadan in a state of junub not because of sexual dream (but on account of intercourse) and he washed himself and observed fast.
Reference : Sahih Muslim 1109bIn-book reference : Book 13, Hadith 96USC-MSA web (English) reference : Book 6, Hadith 2452