The Kitáb-i-Aqdas - The Most Holy Book
Index term: opposition by, under Clergy (Divines)
O Land of Káf and Rá [Kirmán]! We, verily, behold thee in a state displeasing unto God, and see proceeding from thee that which is inscrutable to anyone save Him, the Omniscient, the All-Informed; and We perceive that which secretly and stealthily diffuseth from thee. With Us is the knowledge of all things, inscribed in a lucid Tablet. Sorrow not for that which hath befallen thee. Erelong will God raise up within thee men endued with mighty valour, who will magnify My Name with such constancy that neither will they be deterred by the evil suggestions of the divines, nor will they be kept back by the insinuations of the sowers of doubt. With their own eyes will they behold God, and with their own lives will they render Him victorious. These, truly, are of those who are steadfast.
the destruction of books
In the Tablet of Ishráqát Bahá'u'lláh, referring to the fact that the Báb had made the laws of the Bayán subject to His sanction, states that He put some of the Báb's laws into effect "by embodying them in the Kitáb-i-Aqdas in different words", while others He set aside.
With regard to the destruction of books, the Bayán commanded the Báb's followers to destroy all books except those that were written in vindication of the Cause and Religion of God. Bahá'u'lláh abrogates this specific law of the Bayán.
As to the nature and severity of the laws of the Bayán, Shoghi Effendi in a letter written on his behalf provides the following comment:

The severe laws and injunctions revealed by the Báb can be properly appreciated and understood only when interpreted in the light of His own statements regarding the nature, purpose and character of His own Dispensation. As these statements clearly reveal, the Bábí Dispensation was essentially in the nature of a religious and indeed social revolution, and its duration had therefore to be short, but full of tragic events, of sweeping and drastic reforms. Those drastic measures enforced by the Báb and His followers were taken with the view of undermining the very foundations of Shí'ih orthodoxy, and thus paving the way for the coming of Bahá'u'lláh. To assert the independence of the new Dispensation, and to prepare also the ground for the approaching Revelation of Bahá'u'lláh, the Báb had therefore to reveal very severe laws, even though most of them were never enforced. But the mere fact that He revealed them was in itself a proof of the independent character of His Dispensation and was sufficient to create such widespread agitation, and excite such opposition on the part of the clergy that led them to cause His eventual martyrdom.