Unlawful Sexual Intercourse (Zina) in Islam

Unlawful Sexual Intercourse :

Do not even go close to fornication. It is indeed a shameful act, and an evil way to follow.(Qur'an 17:32)

Tell the believing men that they must lower their gazes and guard their private parts; it is more decent for them. Surely Allah is All-Aware of what they do.(Qur'an 24:30)

** Read Modesty in Islam

And tell the believing women that they must lower their gazes and guard their private parts, and must not expose their adornment, except that which appears thereof, and must wrap their bosoms with their shawls, and must not expose their adornment, except to their husbands or their fathers or the fathers of their husbands, or to their sons or the sons of their husbands, or to their brothers or the sons of their brothers or the sons of their sisters, or to their women, or to those owned by their right hands, or male attendants having no (sexual) urge, or to the children who are not yet conscious of the shames of women. And let them not stamp their feet in a way that the adornment they conceal is known. And repent to Allah O believers, all of you, so that you may achieve success.(Qur'an 24:31)

and those who do not invoke any other god along with Allah, and do not kill a person whom Allah has given sanctity, except rightfully, nor do they fornicate; and whoever does it, shall face the recompense of his sin,(Qur'an 25:68)

O you who believe, when the believing women come to you, seeking bai’ah (a pledge of allegiance) with you that they will not ascribe any partner to Allah, and will not commit theft, and will not commit fornication, and will not kill their children, and will not come up with a false claim (about the parentage of a child) that they falsely attribute (to the sperm of their husbands being dropped) between their hands and their feet (i.e. their private parts), and will not disobey you in what is recognized (in Shariah), then take them in your bai’ah, and pray Allah for their forgiveness. Surely Allah is Most- Forgiving, Very-Merciful.(Qur'an 60:12)

The fornicating woman and the fornicating man, flog each one of them with one hundred stripes. No pity for them should prevail upon you in the matter of Allah’s religion, if you really believe in Allah and the Last Day; and a group of believers must witness their punishment.(Qur'an 24:2)

Narrated 'Ikrima: Ibn 'Abbas i said: Allah's Messenger said, "When a slave (of Allah) commits illegal sexual intercourse then he is not a believer at the time of committing it; and when he steals then he is not a believer at the time of stealing; and when he drinks an alcoholic drink, then he is not a believer at the time of drinking it, and he is not a believer when he commits a murder." 'Ikrima said: I asked Ibn Abbãs, "How is Faith taken away from him?" He said, "Like this," by clasping his hands and then separating them, and added, "But if he repents, Faith returns to him like this," by clasping his hands again.(Sahih Bukhri 6809)

Narrated Abü Hurairah The Prophet (pbuh) said, "The one who commits an illegal sexual intercourse is not a believer  at the time of committing illegal sexual intercourse; and a thief is not a believer at the time of committing theft; and a drinker of alcoholic drink is not a believer at the time of drinking. Yet, (the gate of) repentance is open thereafter."(Sahih Bukhri 6810)

Narrated 'Abdullãh (bin Mas'ud): I said, "O Allah's Messenger! Which is the biggest sin?" He said, "To set up a rival unto Allah, though He Alone has created you." I asked, "What is next (biggest sin)?" He said, "To kill your son lest he should share your food with you." I asked, "What is next?" He said, "To commit illegal sexual intercourse with the wife of your neighbour."(Sahih Bukhri 6811)

Narrated Aba Hurairah  A man came to Allah's Messenger while he was in the mosque, and he called him, saying, "O Allah's Messenger! I have committed illegal sexual intercourse." The Prophet , turned his face to the other side, but that man repeated his statement four times, and after he bore witness against himself four times, the Prophet ; called him, saying, "Are you mad?" The man said,

"No." The Prophet said, "Are you married?" The man said, "Yes." Then the Prophet said, "Take him away and stone him to death."(Sahih Bukhri 6815)