Answered by Shaykh Faraz Rabbani
When you wake up in the morning and you realize that you had a wet dream is it obligatory to do ghusl before prayer or can you get away with it just by doing wudu?
A purificatory bath (ghusl) would be required in such a case, because the Prophet (Allah bless him & give him peace) said, “Water is required by water.” [A rigorously authentic hadith reported by Muslim, from Abu Sa`id al-Khudri (Allah be pleased with him)] That is, one needs to use water for a purificatory bath, if ejaculation takes place.
Muwaffaq al-Din Ibn Qudama (d. 620 AH) mentioned in his masterpiece of Hanbali and comparative fiqh, al-Mughni,
“The exiting of ejaculate with desire makes a purificatory bath (ghusl) obligatory for men and women, whether in waking or sleep. This is the position of the generality of the fuqaha, as Tirmidhi said, and we are not aware of any disagreement on this.” [Ibn Qudama, al-Mughni, 1: 278, Dar Ihya’ al-Turath al-Arabi]
Imam Abu Bakr al-Kasani reported scholarly consensus on this in his Bada’i` al-Sana’i` (1: 36)
As for when actual intercourse takes places, a purificatory bath is obligatory (fard), even if no ejaculation takes place.
Ala’ al-Din Abidin, the 19th Century Damascene faqih and son of Ibn Abidin, said in his al-Hadiyya al-`Ala’iyya:
“A purificatory bath is necessitated by:
a) sperm or female ejaculate that leaves its place of origin with desire [f: whether actual or effective], even if it exits the body without desire, even if without sexual intercourse;
b) the head of the penis entering either private part of a living human being who is fit for sexual intercourse, even without any release of sexual fluids ” [ al-Hadiyya al-`Ala’iyya, ]
Wassalam
Faraz Rabbani
Wassalam,
Faraz Rabbani