Charles Ellicott Commentary Leviticus 18:20

"And thou shalt not lie carnally with thy neighbor`s wife, to defile thyself with her." — Leviticus 18:20 (ASV)

Thy neighbour’s wife. —For committing adultery, which is here branded as a defilement, whether with a betrothed or married woman, both guilty parties incurred the penalty of death by stoning. (Deuteronomy 22:22; Ezekiel 16:38; Ezekiel 16:40; John 8:5.) In Egypt the adulterer received a thousand strokes with a stick, and the guilty woman had her nose cut off, and to this day the criminal wife among the Bedouins is executed by her husband, father, or brother, without any mercy. Both criminals were also punished with death among other Eastern nations.