Praise be to Allaah.
is obligatory on men and woman alike when one of the two following things happens:
When the two “circumcised parts” meet, which is
penetration, i.e. intercourse – even if there is no ejaculation – because the
Prophet (peace and blessings of Allaah be upon
him) said: “When the two circumcised parts meet and the tip of the penis disappears,
ghusl becomes obligatory, whether ejaculation takes place or not.” (Narrated
by Abu Dawood; see Saheeh Sunan Abi Dawood, 209).
Ejaculation – even if the two circumcised parts
do not meet – whether this happens as a result of manual stimulation or otherwise.
The Prophet (peace and blessings of Allaah be upon
him) said: “Water is for water” – i.e., ghusl is required when water (meaning
semen or sexual fluid) is emitted.
regard to fasting, it is not essential for a person to do ghusl before Fajr
starts in order for his fast to be valid. If he starts a day of fasting whilst
he is junub (impure as a result of sexual activity) his fast is till valid.
(See: 70 issues related to fasting). But he should
hasten to do ghusl so that he can pray Fajr on time.
Allaah knows best. May Allaah bless our Prophet Muhammad.
Sheikh Muhammed Salih Al-Munajjid