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.

Bahá’u’lláh, The Kitab-i-Aqdas, p. 200

God hath imposed a fine on every adulterer and adulteress, to be paid to the House of Justice: nine mithqals 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.

Bahá’u’lláh, The Kitáb-i-Aqdas, p. 37

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.

Bahá’u’lláh, The Kitáb-i-Aqdas, p. 200

Yea, in the writings and utterances of the Mirrors reflecting the sun of the Muhammadan Dispensation mention hath been made of “Modification by the exalted beings” and “alteration by the disdainful.” Such passages, however, refer only to particular cases. Among them is the story of Ibn-i-Suriya. When the people of Khaybar asked the focal center of the Muhammadan Revelation concerning the penalty of adultery committed between a married man and a married woman, Muhammad answered and said: “The law of God is death by stoning.” Whereupon they protested saying: “No such law hath been revealed in the Pentateuch.” Muhammad answered and said: “Whom do ye regard among your rabbis as being a recognized authority and having a sure knowledge of the truth?” They agreed upon Ibn-i-Suriya. Thereupon Muhammad summoned him and said: “I adjure thee by God Who clove the sea for you, caused manna to descend upon you, and the cloud to overshadow you, Who delivered you from Pharaoh and his people, and exalted you above all human beings, to tell us what Moses hath decreed concerning adultery between a married man and a married woman.” He made reply: “O Muhammad! death by stoning is the law.” Muhammad observed: “Why is it then that this law is annulled and hath ceased to operate among the Jews?” He answered and said: “When Nebuchadnezzar delivered Jerusalem to the flames, and put the Jews to death, only a few survived. The divines of that age, considering the extremely limited number of the Jews, and the multitude of the Amalekites, took counsel together, and came to the conclusion that were they to enforce the law of the Pentateuch, every survivor who hath been delivered from the hand of Nebuchadnezzar would have to be put to death according to the verdict of the Book. Owing to such considerations, they totally repealed the penalty of death.” Meanwhile Gabriel inspired Muhammad’s illumined heart with these words: “They pervert the text of the Word of God.”[1] [1 Qur’án 4:45.]

Bahá’u’lláh, The Kitab-i-Iqan, p. 84

When we realize that Bahá’u’lláh says adultery retards the progress of the soul in the after life -- so grievous is it . . . we see how clear are our teachings on these subjects.

Shoghi Effendi, Lights of Guidance, p. 344

There is a Tablet from ‘Abdu’l-Bahá which states that the year of waiting is waived in the case of an unfaithful wife. This aspect of the Bahá’í law of divorce, however, will need elucidation and supplementary legislation by the Universal House of Justice. Therefore, at the present time, in divorce cases such as the one you cited, the husband must still observe the year of waiting, which involves payment of the wife's expenses during this period.

Letter from the Universal House of Justice, June 17, 1987, to a National Spiritual Assembly, found in NSA USA - Developing Distinctive Bahá’í Communities

This aspect of the Bahá’í law of divorce, however, will need elucidation and supplementary legislation by the House of Justice. Therefore, at the present time, the year of waiting must be observed when adultery on the part of either party is proven.

Universal House of Justice to an individual believer, 28 April 1974

The severe punishment imposed upon adultery by Bahá’u’lláh we can understand. When marriage is entered into in the Bahá’í spirit and the promises are made not to one another but to God –“Promise not that which you cannot fulfill” commands Bahá’u’lláh — adultery is a complete violation of that pledge and a negation of the forces of unity; it is spiritual anarchy affecting both the innocent and the guilty; it is blasphemy towards that Source to which both turn.

The Bahá’í World – A Biennial International Record – Volume VII – 93 and 94 of the Bahá’í Era – April 1936-1938 A.D. – Prepared under the supervision of the National Spiritual Assembly of the Bahá’ís of the United States and Canada with the approval of Shoghi Effendi