“the transgressions of the parents will affect four generations of their descendants.” – ‘Abdu’l-Baha explains

Thou hadst asked about the meaning of the statement “the transgressions of the parents will affect four generations of their descendants.” Know thou that spiritual diseases are like physical ones. Thou seest that if a person is afflicted with a chronic physical illness, traces of his ailment will linger in three or four generations of his offspring. Likewise, should he be afflicted with a spiritual disease, that of an immoral character, this will have a great influence on his progeny, for upbringing exerteth an astounding influence and that person’s character will be passed on to his descendants. A powerful force is thus needed to eliminate that influence. By this “transgression” is meant immorality and heedlessness of God. In truth, this transgression is the breaking of the Covenant, the abasement resulting from which will linger in the descendants for four generations.

And now, I hope that thou shalt become the cause of the illumination of souls, so that they may acquire a heavenly nature, and that thy goodly character may exert its influence upon a vast number of people. 

- ‘Abdu’l-Baha  (From a Tablet, ‘Additional Tablets, Extracts and Talks’, Online Baha’i Reference Library of the Baha’i World Center)

The basis on which they pronounced the death sentence against the Báb – ‘Abdu’l-Baha explains

…consider the basis on which they pronounced the death sentence against the Most Exalted One, the Báb—may my life be a sacrifice unto Him! Mullá Muhammad-i-Mamaqání cried out, “O people! In the Qur’án God saith: ‘No doubt is there about this Book: It is a guidance unto the God-fearing’ [Qur’án 2:2]; that is, it guideth aright all humanity. It is also clearly stated: ‘But He is the Apostle of God and the Seal of the Prophets.’ [Qur’án 33:40] How can we regard such an explicit statement as the source of error, while it is guidance itself? This person who claimeth to be a descendant of the Prophet hath indeed destroyed the foundation laid down by Him!” He then mentioned, one by one, some of the laws revealed in the Bayán—laws that were later abrogated in the Kitáb-i-Aqdas. Thereupon, he ordered the emblem of the Báb’s noble lineage to be removed from His head, [1] and issued, without hesitation and with the utmost malice, the sentence of His death. 

- ‘Abdu’l-Baha  (From a Tablet; ‘Light of the World’)

[1] His turban

A dialogue between Baha’u’llah and the Maid of Heaven

O Pen! Announce unto the Maid of Paradise:

“By God! This day is thy day. Come forth as thou willest, and array thyself as thou pleasest with the broidered robe of names and the silken vesture of immortality. Emerge then from thine eternal habitation even as the sun that dawneth from the countenance of Bahá. Descend from thy lofty heights and, standing betwixt earth and heaven, lift the veil of concealment from thy luminous face and shine forth above the horizon of creation as the black-eyed Damsel, that haply the most great veil may be torn away from the eyes of these people and they may behold the Scene of transcendent glory, the Beauty of God, the Most Holy, the Most Powerful, the Best-Beloved.”

“O Ancient Beauty! The unbelievers, verily, are lost in the stupor of idle fancy and are powerless to turn their eyes towards the most hallowed Court. Through the sovereign potency of Thine inviolable protection, Thou hast shielded me beneath the veils of light and guarded my beauty from the gaze of Thine enemies. Thine is the power to command; Thou ordainest as Thou pleasest through Thy word ‘Be’, and it is.”

“O Maid of Bahá! Step forth from the court of eternity, but let not thy most pure gaze linger upon the faces of mortal men. I swear by the one true God! None save them that are possessed of true insight can ever hope to behold thee in this most sublime vision. Leave the kingdom of names on thy right and the dominion of attributes on thy left, and shine forth by My leave above the horizon of Mine inviolable protection, divested of all that hath been created in the realm of Revelation and shorn of all that hath appeared in the kingdom of creation, that thou mayest manifest the beauteous image of God in all regions. Intone, then, the sweetest of melodies betwixt earth and heaven, that all existence may be detached from aught save the face of thy Lord, the Most Holy, the Most Gracious, the Well-Beloved. Beam forth above the horizon of the Riḍván with the beauty of the All-Merciful, and let thy fragrant locks flow upon thy bosom, that the perfume of the garment of thy most gracious Lord may be diffused throughout the world. Hide not thy luminous form from the eyes of the concourse of Revelation, and withhold not thine ethereal veil of holiness from the gaze of the people. Present thyself, then, before the Throne with thy locks flowing, thine arms bejewelled, thy countenance blushing, thy cheeks aglow, and thine eyes adorned, and take hold of the snow-white chalice in My most exalted Name. Proffer then to the denizens of the realm of eternity the crimson wine of Mine all-glorious Beauty, that haply the concourse of Revelation may sanctify their souls in this most august Festival by virtue of this pure draught, and that they may emerge from behind the veil of concealment through the power of Mine almighty and all-powerful, Mine all-subduing and self-subsisting sovereignty.”

1844: Conditions in Shiraz immediately after the Declaration of the Báb – described by historian A. L. M. Nicolas

“This city [Shiraz] became the arena for passionate discussions which profoundly troubled the general peace. The curious, the pilgrims, the scandal-mongers met there commenting upon the news, approving or blaming, exalting the young Siyyid [the Báb], or, on the contrary, heaping upon him maledictions and insults. Everyone was excited and enervated. The Mullás saw with bitter anxiety the growing number of adherents to the new doctrine and their resources diminished correspondingly. It became necessary to act, as prolonged tolerance would empty the Mosques of their believers who were convinced that since Islám did not defend itself, it acknowledged defeat. On the other hand, Husayn Khán, governor of Shíráz, Nizámu’d-Dawlih, feared that, in letting things drift, the scandal would become such that later it would be impossible to suppress it; that would be to court disgrace. Besides, the Báb did not content himself with preaching, he called to himself men of good-will. ‘He who knows the Word of God and does not come to His assistance in the days of violence is exactly like those who turned away from the testimony of his holiness Husayn, son of ‘Alí, at Karbilá. Those are the impious ones!’ (Kitab-i-Baynu’l-Haramayn.) The civil interests concurring with the interests of heaven, Nizámu’d-Dawlih and Shaykh Abú-Turáb, the Imám-Jum’ih agreed that humiliation should be inflicted upon the innovator such as would discredit him in the eyes of the populace; perhaps thus they might succeed in quieting things.” 

- A. L. M. Nicolas’ (“Siyyid ‘Alí-Muḥammad dit le Báb,” pp. 229–230; Footnotes to chapter 8 provided by Shoghi Effendi in 'The Dawn-Breakers')