As was also mentioned in the first principle, the Bāb and his book, Bayān hold a special importance for Baha’i’s. This is what Bahā’u’llāh says, about the book of Bayan:
Refer to it, for a letter from it will suffice the entirety of the people of the earth. And surely God has stated all things in the evident book.
Reference: Asad-Allāh Fāḍil Māzandarānī, Asrār al-āthār khuṣūṣī, vol. 2, p. 102.
He also says:
I [swear by] He who in His hand is my soul and my essence, a single letter from the Bayān is dearer to me than everything that is in the heavens and the earth.
Reference: Asad-Allāh Fāḍil Māzandarānī, Asrār al-āthār khuṣūṣī, vol. 5, p. 333.
Even though Bahā’u’llāh abrogated the book of the Bayān, he had stresses many times that he had no intention to do so. Rather, he had stated that he intended to reinforce its decrees:
Say: The polytheists thought that we might want to abrogate what was revealed unto the Point of Bayan (Nuqṭat al-Bayān which means the Bab). Say: By my Merciful Lord, even if we had intended [to do] what they had thought, no one was allowed to object to God who has created everything . . . but God has desired by this manifestation [meaning Bahā’u’llāh himself] to reinforce what has been revealed by the Point of Bayan . . . thus we will reinforce his decrees and will prove his writings [or signs] on earth with power and authority.
Reference: Bahā’u’llāh, Badī`, p. 390.
This is while many of the laws that have been put forth by the Bab in the book of Bayan are unacceptable to any sound mind.
Books, Writings, and Teaching
Teaching a book other than the book of Bayān is not allowed unless it has in it what is related to speculative theology (kalām). [Teaching] those [sciences] which have been invented such as logic (manṭiq), principles of jurisprudence (uṣūl), and other [sciences], are not permitted for those who have faith.
Reference: The Bāb, Farsi Bayān, unit 4, chap. 10.
You have been prohibited in the Bayān from having more than nineteen books. If you do so, you will be fined 19 mithqāls (Every mithqāl is equal to about 3.6 grams) of gold.
Reference: The Bāb, Arabic Bayān, unit 11, chap. 7.
Do not argue but by the verses [of the Bayān] for whoever does not argue using them has no knowledge, and do not mention any miracle [but this book]!
Reference: The Bāb, Arabic Bayān, unit 6, chapter 8.
The best trade is to acquire all of the Bāb’s books. Once this is fulfilled sustenance will flow down like rain:
If possible acquire all the writings of the Point (meaning the Bāb) even if they are in printed form (not hand-written) for sustenance will descend upon those who possess these like rain. Say O my servants, this is the best trade!
Reference: The Bāb, Arabic Bayān, unit 9, chap. 10.
And finally some very disturbing words:
Say O Muḥammad, my teacher. Do not hit me before my age finishes five even for a moment for my heart is very very soft. After that discipline me but not more than I can bear. If you want to hit me do not [hit me] more than five times. And do not hit me on my flesh (laḥm) unless there is a covering over it. If you exceed [these guidelines] your wife will be illegal for you for nineteen days. If you forget and if you don’t have a companion, then you must give in charity for every beating nineteen mithqāls of gold if you want to be faithful.
Reference: Bāb, Arabic Bayān, unit 6, chapter 11.
These words are very disturbing because he is giving orders to his teacher to do something not in the future, but in the past! He is telling his teacher to not hit him until his age passes five. These words were uttered when the Bab was about 29 years old! He then threatens the teacher that if he surpasses these orders he will make his wife illegal for him for nineteen days (!) or if he doesn’t have a companion (wife) he would have to pay nineteen mithqāls of Gold. Are these words in conformity with reason and science?
Food and Medicine
Using medicine is forbidden:
You must not possess, buy, sell, or use medicine, intoxicants, and higher than those!
Reference: The Bāb, Arabic Bayān, unit 9, chap. 8.
Drinking donkey milk is also forbidden and by not drinking it people will become pious:
Do not drink donkey milk! And do not load it and other animals with what they cannot bear. This is what God has made incumbent upon you so that you may become pious!
Reference: The Bāb, Arabic Bayān, unit 10, chap. 15.
Do not spoil eggs for they are the Bāb’s food on the Day of Resurrection:
Do not hit eggs on something that will spoil their insides before they are cooked, for this is the food of the Primal Point (the Bāb) and his followers in the Day of Resurrection (Qiyāma) so that you may be grateful.
Reference: The Bāb, Arabic Bayān, unit 10, chap. 15.
This order is itself very unique for according to the Baha’is, the Day of Resurrection, is the proclamation of Bahā’u’llāh. The Bāb had been dead for many years when this occurred so how could his food be eggs on that day?
Going on Journeys
Whoever forces anyone in a journey—even one step—or enters someone’s house before permission is given, or forces him out of his house without his permission, or unlawfully summons him from his home, then his wife will be illegal for him for 19 months!
Reference: The Bāb, Arabic Bayān, unit 6, chap. 16.
Permission is given for going on journeys for one of three reasons:
Do not go on journeys but  for the sake of God and  if you are going to (visit) He Whom God Shall Make Manifest or  (visiting) those who have faith in him. And He orders you to take the leaves of trees and eat them [!] and walk above [!] the earth with your legs!
Reference: The Bāb, Lauḥ haykal al-dīn, unit 6, chap. al-Badī.
The order has been given to eat the leaves of trees and to walk above the ground with the legs! Pay attention, he says above (fauq) the ground not on the ground!
Courtesy: Twelve Principles – A Comprehensive Investigation on the Bahai Teachings