(13) باب صِحَّةِ صَوْمِ مَنْ طَلَعَ عَلَيْهِ الْفَجْرُ وَهُوَ جُنُبٌ
Sulaiman b. Yasar reported that he asked Umm Salama whether a person (who gets up) in the morning in a state of junub should observe fast. She said:
The Messenger of Allah (ﷺ) (at times) got up in the morning in a state of junub, not because of sexual dreams (but on account of intercourse at night), and then observed fast.
Reference: Sahih Muslim 1109 e
In-book reference: Book 13, Hadith 100
USC-MSA web (English) reference(deprecated numbering scheme): Book 6, Hadith 2456