John Calvin Commentary Leviticus 18:20

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

The purpose of this passage is the same as that of the preceding ones. For, while all fornication pollutes a man, there is grosser impurity in adultery, because the sanctity of marriage is violated, and by the mixing of seed a spurious and illegitimate offspring results. Therefore, God has justly listed this crime among the abominations of the Gentiles, as can be more clearly seen from the introduction of the chapter from which this passage is taken.