The Kitáb-i-Aqdas - The Most Holy Book
Index term: receives fines for sexual offenses, under House(s) of Justice
k49.
God hath imposed a fine on every adulterer and adulteress, to be paid to the House of Justice: nine mithqáls of gold, to be doubled if they should repeat the offence. Such is the penalty which He Who is the Lord of Names hath assigned them in this world; and in the world to come He hath ordained for them a humiliating torment. Should anyone be afflicted by a sin, it behoveth him to repent thereof and return unto his Lord. He, verily, granteth forgiveness unto whomsoever He willeth, and none may question that which it pleaseth Him to ordain. He is, in truth, the Ever-Forgiving, the Almighty, the All-Praised.
n77.
God hath imposed a fine on every adulterer and adulteress, to be paid to the House of Justice
Although the term translated here as adultery refers, in its broadest sense, to unlawful sexual intercourse between either married or unmarried individuals (see note 36 for a definition of the term), 'Abdu'l-Bahá has specified that the punishment here prescribed is for sexual intercourse between persons who are unmarried. He indicates that it remains for the Universal House of Justice to determine the penalty for adultery committed by a married individual. (See also Q&A 49.)
In one of His Tablets, 'Abdu'l-Bahá refers to some of the spiritual and social implications of the violation of the laws of morality and, concerning the penalty here described, He indicates that the aim of this law is to make clear to all that such an action is shameful in the eyes of God and that, in the event that the offence can be established and the fine imposed, the principal purpose is the exposure of the offenders -- that they are shamed and disgraced in the eyes of society. He affirms that such exposure is in itself the greatest punishment.
The House of Justice referred to in this verse is presumably the Local House of Justice, currently known as the Local Spiritual Assembly.
q11.
 
Question: If intercourse take place between a couple during their year of patience, and they become estranged again thereafter, must they recommence their year of patience, or may the days preceding the intercourse be included in the reckoning of the year? And once divorce hath taken place, is it necessary that a further period of waiting be observed?
Answer: Should affection be renewed between the couple during their year of patience, the marriage tie is valid, and what is commanded in the Book of God must be observed; but once the year of patience hath been completed and that which is decreed by God taketh place, a further period of waiting is not required. Sexual intercourse between husband and wife is forbidden during their year of patience, and whoso committeth this act must seek God's forgiveness, and, as a punishment, render to the House of Justice a fine of nineteen mithqáls of gold.