For this is an heinous crime - This expresses Job's sense of the enormity of such an offence. He felt that there was no palliation for it; he would in no way, and on no pretence, attempt to vindicate it.
An iniquity to be punished by the judges - A crime for the judges to determine on and decide. The sins which Job had specified before this, were those of the heart; but here he refers to a crime against society - an offence which deserved the interposition of the magistrate. It may be observed here, that adultery has always been regarded as a sin "to be punished by the judges." In most countries it has been punished with death; see the notes at John 8:5.

For this is a heinous crime - Mr. Good translates,
"For this would be a premeditated crime,
And a profligacy of the understanding."
See also Job 31:28. That is, It would not only be a sin against the individuals more particularly concerned, but a sin of the first magnitude against society; and one of which the civil magistrate should take particular cognizance, and punish as justice requires.

For this is an heinous crime,.... Adultery; it is contrary to the light of nature, and is condemned by it as a great sin, Genesis 20:9; as well as contrary to the express will and law of God, Exodus 20:14; and, though all sin is a transgression of the law of God, and deserving of death; yet there are some sins greater and more heinous than others, being attended with aggravating circumstances; and such is this sin, it is a breach of the marriage contract and covenant between man and wife; it is doing injury to a man's property, and to that which is the nearest and dearest to him, and is what introduces confusion into families, kingdoms, and states; and therefore it follows:
yea, it is an iniquity to he punished by the judges; who might take cognizance of it, examine into it, and pass sentence for it, and execute it; and, if they neglect do their duty, God, the Judge of all the earth, will punish for it in the world to come, unless repented of: "for whoremongers and adulterers God will judge", Hebrews 13:4; the punishment of adultery was death by the law of God, and that by stoning, as appears from Leviticus 20:10; and it is remarkable, that the Heathens, who were ignorant of this law, enjoined the same punishment for it; so Homer (e) introduces Hector reproving Paris for this sin, and suggests to him, that if he had his deserved punishment, he would have been clothed with a "stone coat", as he beautifully expresses it; which Suidas (f) explains, by being overwhelmed with stones, or stoned; as Eustathius (g).
(e) Iliad. 3. v. 57. (f) In voce (g) In Homer. ibid.

In the earliest times punished with death (Genesis 38:24). So in later times (Deuteronomy 22:22). Heretofore he had spoken only of sins against conscience; now, one against the community, needing the cognizance of the judge.

This - Adultery. It is - Hebrews. an iniquity of the judges; which belongs to them to take cognizance of, and to punish, even with death; and that not only by the law of Moses, but even by the law of nature, as appears from the known laws and customs of the Heathen nations.