(32) باب حكْمِ الْمَنِيِّ
'Amr b. Maimun said:
I asked Sulaiman b. Yasar whether the semen that gets on to the garment of a person should be washed or not. He replied: A'isha told me: The Messenger of Allah (ﷺ) washed the semen, and then went out for prayer in that very garment and I saw the mark of washing on it.
Reference: Sahih Muslim 289a
In-book reference: Book 2, Hadith 138
USC-MSA web (English) reference(deprecated numbering scheme): Book 2, Hadith 570