Sex outside of the institution of marriage is forbidden in Islam and punishable by flogging - if four witnesses with consistently honest reputations testify to having seen the act of full sexual intercourse take place. Those who accuse others of adultery or fornication without the full evidence of four witnesses are also punishable according to Islamic law. This is to prevent undue slander against chaste men and women and to prevent the spread of destructive rumours, gossip and scandal.

The requirement of four witnesses to have witnessed the full act of intercourse for any given case is an extremely high threshold for evidence and means effectively Islamic law does not seek to punish individuals for acts committed in the privacy of their own homes but intervenes when they graduate to public indecency, flaunting and promoting their promiscuity in public.

Some sects and Muslim-majority states have claimed the death penalty is applicable to fornicators and adulterers. This is entirely against the teachings of Islam as found in the primary scripture of the Quran:

The adulteress and the adulterer (or the fornicatress and the fornicator) — flog each one of them with a hundred stripes. And let not pity for the twain take hold of you in executing the judgment of Allah, if you believe in Allah and the Last Day. And let a party of the believers witness their punishment. The adulterer (or fornicator) shall not marry but an adulteress (or fornicatress) or an idolatrous woman, and an adulteress (or fornicatress) shall not marry but an adulterer (or fornicator) or an idolatrous man. That indeed is forbidden to the believers. And those who calumniate chaste women but bring not four witnesses — flog them with eighty stripes, and never admit their evidence thereafter, and it is they that are the transgressors, Except those who repent thereafter and make amends, for truly Allah is Most Forgiving, Merciful.

- Quran 24:3-6

All Muslims accept the primacy of the Quran as the word of God and so no tradition can overrule its teachings. The verses above explain the only punishment for fornication and adultery is flogging. If the adulterer or fornicator were to be killed, the Quran would have no need to warn believers against marrying them in future - as the dead have no opportunity to marry. Moreover, elsewhere the Quran states some people may be given half the normal punishment for the same crime. There is no way to give half the death penalty, once again illustrating 100 stripes (or 50, if halved) is the only punishment prescribed for adultery and fornication in Islam.

See also

• Rape
• Women in Islam