Leviticus 18:20

Moreover, thou shalt not lie carnally with thy neighbour's wife,.... Which is adultery, and a breach of the seventh command,

Exodus 20:14:

to defile thyself with her; not only adultery is a defiling a man's wife, as it is sometimes called, but the adulterer defiles himself: all sin is of a defiling nature, but especially this, which defiles a man both in soul and body, and brings a blot and stain upon his character, which shall not be wiped off, Proverbs 6:32.