The Book of Menstruation - Sahih Muslim 343 b

The Apostle of Allah (ﷺ) observed: Bathing is obligatory in case of seminal emission.

Commentary on the Hadith

This noble hadith establishes the fundamental Islamic ruling concerning ritual purity. When a person experiences the emission of semen, whether during sleep (i.e., a wet dream) or while awake, the complete ritual bath (ghusl) becomes obligatory upon them.

The wisdom behind this ruling is profound. Seminal emission constitutes a major physical discharge that nullifies the state of ritual purity (wudu'). Consequently, acts of worship that require purity, such as the formal prayer (salah), circumambulation of the Ka'bah (tawaf), and the recitation of the Qur'an by touch, are prohibited until the major ritual impurity is removed by performing ghusl.

The obligation applies regardless of whether the emission was accompanied by sensual pleasure or not. The defining factor is the emergence of the fluid itself. The procedure for ghusl, as detailed in other authentic narrations, involves the intention to purify oneself, followed by washing the entire body, ensuring that water reaches every part, including the roots of the hair.

This ruling underscores the importance Allah places on both physical and spiritual cleanliness for His servants, making purity a prerequisite for drawing near to Him in acts of devotion.