Yahya related to me from Malik from Ibn Shihab from Urwa ibn az- Zubayr that Umm Sulayman said to the Messenger of Allah, may Allah bless him and grant him peace, "Should a woman do ghusl when she experiences the same as a man in her sleep?" The Messenger of Al lah said to her, "Yes, she should do ghusl. "A'isha said to her, "Shame on you! Does a woman see that?" (i.e. a liquid.) The Messenger of Allah, may Allah bless him and grant him peace, said to her, "May your right hand be full of dust. From where does family resemblance come?"
Muwatta Malik Book 2, Hadith 85
← Previous Hadith Yahya related to me from Malik from Hisham ibn Urwa from his father fromYahyaibn Abd ar-Rahman ibn Ha ib that he had set off for Mumra with Umar ibn al-Khattab in a party of riders, among whom was Amr ibn al-As. Umar ibn al-Khattab dismounted for a rest late at night on a certain road near a certain oasis. Umar had a wet dream when it was almost dawn and there was no water among the riding party. He rode until he came to some water and then he began to wash off what he saw of the semen until it had gone. Amr ibn al-As said to him, "It is morning and there are clothes with us, so allow your garment to be washed. ''Umar ibn al-Khattab said to him, "I am surprised at you, Amr ibn al-As! Even if you could find clothes, would everybody be able to find them? By Allah, if I were to do it, it would become a sunna. No, I wash what I see, and I sprinkle with water what I do not see."

Malik spoke about a man who found traces of a wet dream on his clothes and did not know when it had occurred and did not remember anything he had seen in his sleep. He said, "Let the intention of his ghusl be from the time when he last slept, and if he has prayed since that last sleep he should repeat it. This is because often a man has a wet dream and sees nothing, and often he sees something but does not have an emission. But, if he finds liquid on his garment he must do ghusl. This is because Umar repeated what he had prayed after the time he had last slept and not what was before it."

Muwatta Malik Book 2, Hadith 84 Next Hadith → Yahya related to me from Malik from Hisham ibn Urwa from his father from Zaynab bint Abi Salama that Umm Salama, the wife of the Prophet, may Allah bless him and grant him peace, said, "Umm Salama, the wife of Abu Talha al-Ansari, came to the Messenger of Allah, may Allah bless him and grant him peace, and said, 'Messenger of Allah! Allah is not ashamed of the truth-does a woman have to do ghusl if she has had an erotic dream?' He said, 'Yes, if she sees any liquid.' "

Muwatta Malik Book 2, Hadith 86