Thou shalt not commit adultery

Thou shalt not bear false witness against thy neighbour.The transgression of commandments is also called uncleanliness or defilement.

[4] If a husband suspected his wife of adultery, the ordeal of the bitter water could be performed to determine her guilt or innocence.

Changes in punishment for adultery were enacted: The adulterer was scourged, and the husband of the adulteress was compelled to divorce her,[8] and she lost all her property rights under her marriage contract.

[13] The mitzvah to practice sexual relations only within marriage is affirmed by Orthodox, Conservative, and Reform rabbis into modern times.

"[16] However, some commentators, including Thomas Aquinas, say that Jesus was making the connection with the commandment, "You shall not covet your neighbor's wife.

"[17] According to the gospels, Jesus quoted the book of Genesis regarding the divine origin of the marriage relationship, concluding, "So they are no longer two, but one flesh.

"Stop depriving one another, except by agreement for a time that you may devote yourselves to prayer, and come together again lest Satan tempt you because of your lack of self-control.

For this reason, he recommends that most people are better off married, in order to preclude being tempted beyond what they can bear or going through life "burning with passion.

This exercise of restraint in order to keep the commandment against adultery is also seen as important practice for fidelity within marriage: Those who are engaged to marry are called to live chastity in continence.

John Calvin understood the commandment against adultery to extend to sexual relations outside of marriage: Although one kind of impurity is alone referred to, it is sufficiently plain, from the principle laid down, that believers are generally exhorted to chastity; for, if the Law be a perfect rule of holy living, it would be more than absurd to give a license for fornication (sexual relations between persons not married to each other), adultery alone being excepted.

"[36] Henry supports his interpretation with Matthew 5:28, where Jesus warns that whoever looks at a (married) woman lustfully has already committed adultery with her in his heart.

"[37]John Wesley believed this scripture and the sure judgment of God, even though adulterers "frequently escape the sentence of men.

"[38] Martin Luther observed that there were many more people in his day who were unmarried for various reasons than in biblical times, which condition increased both temptation and sexual activities that are displeasing to God: But because among us there is such a shameful mess and the very dregs of all vice and lewdness, this commandment is directed also against all manner of unchastity, whatever it may be called; ...For flesh and blood remain flesh and blood, and the natural inclination and excitement have their course without let or hindrance, as everybody sees and feels.

In order, therefore, that it may be the more easy in some degree to avoid unchastity, God has commanded the estate of matrimony, that every one may have his proper portion and be satisfied therewith … Luther neither condemns nor denies human sexuality, but, like the Apostle Paul, claims that God instituted the marriage relationship to provide for its proper enjoyment.

Luther comments that each spouse should intentionally cherish the other, and that this will contribute to love and a desire for chastity, which will make fidelity easier.

For where conjugal chastity is to be maintained, man and wife must by all means live together in love and harmony, that one may cherish the other from the heart and with entire fidelity.

The so-called "Wicked Bible", printed in 1631, omits the word "not", reading "Thou shalt commit adultery."