Q: Which is the seventh commandment?
A: The seventh commandment is, Thou shalt not commit adultery.
Q: What is required in the seventh commandment?
A: The seventh commandment requireth the preservation of our own, and our neighbour’s chastity, in heart, speech, and behaviour.
Q: What is forbidden in the seventh commandment?
A: The seventh commandment forbiddeth all unchaste thoughts, words, and actions.
(Questions LXX, LXXI and LXXII from the Westminster Shorter Catechism.)