Sexual-intercourse between a man and a woman not married to one another is regarded as a great sin in Islaam. There are many verses of the Qur'an and Prophetic statements with regard to this issue and we relate just a few below. Each indicates the seriousness of adultery and makes it crystal clear that there is no room for it being an acceptable behavior in Islaam. Allah says in the Qur'an: "Do not come near to adultery. Verily, it is a faahisha (a great and shameful sin) and an evil way (that leads someone to Hell unless Allah forgives him." (Al-Israa' 17:32)
Prophet Muhammad (peace be upon him) said: "There is no sin after Shirk (associating partners to Allah) greater in the sight of Allah than a drop of semen which a man places in the womb which is not lawful for him." (Al-Bukhari, Kitabul-Hudood) He also said: "The adultery of the legs is walking (with bad intention towards a woman who is not lawful for a man) and the adultery of the hands is touching and patting (such a woman) and the adultery of the eyes is the passionate glance." (Al-Bukhari).
An incident during the life of our dear Prophet Muhammad [peace be upon him]
Abu Umamah narrated: A certain young man came to the Prophet (peace be upon him) and said: "O Messenger of Allah permit me to commit adultery." The Companions were annoyed at this arrogant attitude of his and with no attempt at concealment of their feelings in this behalf, berated him, and demonstrated open disgust for his insolent request.
The Prophet (peace be upon him) asked the young man to come closer and he did so. Then he asked him to take a seat and he obeyed.
The Prophet (peace be upon him) then started to ask him: "Would you like such (i.e. adultery) for your mother?" He (the man) replied, "No, by Allah. May Allah sacrifice me for you."
The Prophet (peace be upon him) said, "Other people do not like it either for their mothers. Would you then like it for your daughter (i.e. adultery)?" He replied, "No by Allah. May my life be sacrificed for you."
The Prophet (peace be upon him) said, "Others too do not like it for their daughters. Would you like if for your sister?"
He replied, "No by Allah. May my life be sacrificed for you." The Prophet said, "Other people do not like it for their sisters. Would you like it for your paternal aunt?"
He replied, "No by Allah. May my life be sacrificed for you." The Prophet said, "Other people dislike it for their paternal aunts. Would you like it for your maternal aunt?"
He replied, "No by Allah. May my life be sacrificed for you."
The Prophet (peace be upon him) said, "Others too do not like it for their maternal aunts."
He (the narrator) then said, "He (the Prophet, peace be upon him) then put his hand on the man's chest and said, "Oh Allah forgive his sin, cleanse his heart, and make chaste his private parts."
Thereafter the young man never even looked at anything (prohibited by Allah) [and nothing was more hateful to him than Adultery]. (Ahmad).
The Prophet (peace be upon him) also said, "Whenever a man is alone with a woman the Devil makes a third." (Al-Tirmidhi 3118)
"When a slave (of Allah) commits illegal sexual intercourse, he is not a believer at the time of committing it." (Saheeh Bukhaari)
We pray that Allah Ta'ala protects us all from this horrendous sin. Aameen.