Despite widespread cultural condemnation of adultery in many Muslim countries, the religion's actual beliefs and teachings in terms of this question are actually quite difficult to ascertain. The Qu'ran itself does condemn adultery, but does not pronounce any consequences. The Hadith, a separate body of literature depicting the life of Muhammad, Islam's founder and prophet, go into more detail. These writings are widely accepted in the Muslim world, but do not have the Qur'an's authoritative status. An apocryphal story and the general interpretation of Sharia law in some places also play a role in shaping Islam's teachings on infidelity.

The Qur'an and Infidelity

The Qu'ran condemns infidelity, but does not pronounce any exact punishment. Passage 17:32 reads, "And do not approach adultery, for verily it is a great sin and an evil way." Another passage, 28:68-69 proclaims that followers of Muhammad "do not commit adultery -- and whoever does this shall meet a full penalty." Sometimes, the "full penalty" in this verse is translated as "the penalty of sin." This makes it unclear whether the verse is referring to an unspoken penalty or that the state of being in sin is the punishment. There is a separate verse, 24:2, that calls for "fornicators or adulterers" to be given lashes as well, but not death, though it is unclear if this refers to married or unmarried sex.

The Hadith and Infidelity

The Hadith is a body of books that show portions of Muhammad's life. In these works, much more detail on the specific consequences of marital infidelity come to light. The most common punishment for adultery in the Hadith is stoning to death. In several scenes, people who have committed adultery, both male and female, are brought before Muhammad, and he sentences them to this fate. In one instance, a pregnant woman admits to having committed adultery, and Muhammad allows her to give birth, then commands she be stoned. In another, Muhammad commands that a man be planted in the ground and stoned. In a separate hadith, Muhammad says that infidelity is one of the justified reasons for killing another person, and in his final address to his people before his last pilgrimage, Muhammad is quoted as saying "The adulterer must be stoned."

Sharia and Infidelity

Because the Qur'an and the Hadith do not specifically approach all issues, Sharia law has been used in some places with Muslim majorities to fill in the gaps. If neither the Qur'an nor the Hadith speak directly to an issue, then other laws can speak to them as long as they do not contradict the body of texts. Therefore, in some places, the penalty for infidelity is death. Sometimes, several witnesses must step forward to corroborate the charges. It is important to understand that due to its versatile nature, Sharia law can be different in different places, and cannot to attributed to Islam as a whole.

Other Islamic Figures and Infidelity

There are apocryphal stories that suggest Muhammad intended to include a verse in the Qur'an expressly calling for adulterers to be stoned to death. In one, Aisha, the wife of Muhammad, told people about a verse written on a palm leaf and intended to be added to the Qur'an, which called for adulterers to be stoned to death, but the leaf was eaten by a goat before it could be added. Also, Umar, the second caliph, or leader, of Islam, is quoted in some hadith as saying that a verse was revealed to Muhammad and forgotten. Several other hadith back up this claim.