In general, the laws of the Kitáb-i-Aqdas are stated succinctly. An example of this conciseness can be seen in the fact that many are expressed only as they apply to a man, but it is apparent from the Guardian’s writings that, where Bahá’u’lláh has given a law as between a man and a woman, it applies mutatis mutandis between a woman and a man unless the context makes this impossible. For example, the text of the Kitáb-i-Aqdas forbids a man to marry his father’s wife (i.e. his stepmother), and the Guardian has indicated that likewise a woman is forbidden to marry her stepfather. This understanding of the implications of the Law has far-reaching effects in light of the fundamental Bahá’í principle of the equality of the sexes, and should be borne in mind when the sacred Text is studied. That men and women differ from one another in certain characteristics and functions is an inescapable fact of nature and makes possible their complementary roles in certain areas of the life of society; but it is significant that ‘Abdu’l-Bahá has stated that in this Dispensation "Equality of men and women, except in some negligible instances, has been fully and categorically announced." Mention has already been made of the intimate relationship between the Kitáb-i-Aqdas and the Holy Books of previous Dispensations. Especially close is the relationship to the Bayán, the Book of Laws revealed by the Báb. It is elucidated in the following excerpts from letters written on behalf of the Guardian: Shoghi Effendi feels that the unity of the Bahá’í Revelation as one complete whole embracing the Faith of the Báb should be emphasized... The Faith of the Báb should not be divorced from that of Bahá’u’lláh. Though the teachings of the Bayán have been abrogated and superseded by the laws of the Aqdas, yet due to the fact that the Báb considered Himself as the Forerunner of Bahá’u’lláh, we would regard His Dispensation together with that of Bahá’u’lláh as forming one entity, the former being introductory to the advent of the latter. The Báb states that His laws are provisional and depend upon the acceptance of the future Manifestation. This is why in the Book of Aqdas Bahá’u’lláh sanctions some of the laws found in the Bayán, modifies others and sets aside many. Just as the Bayán had been revealed by the Báb at about the mid-point of His Ministry, Bahá’u’lláh revealed the Kitáb-i-Aqdas around 1873, some twenty years after He had received, in the Síyáh-C̱ẖál of Ṭihrán, the intimation of His Revelation. In one of His Tablets He indicates that even after its revelation the Aqdas was withheld by Him for some time before it was sent to the friends in Iran. Thereafter, as Shoghi Effendi has related: