Bahá’u’lláh’s Book of Certitude, considered by many Bahá’ís to be his premier work, is primarily concerned with arguing that his predecessor, the Báb, was indeed what he claimed to be: the Voice, Image, and Manifestation of God. In making this defense of the Báb, Bahá’u’lláh cited the Qur’án nearly 150 times. It is an apology firmly rooted in Islamic scripture. It is not the purest form of revelation inasmuch as it is a book about revelation, to say nothing of the fact that it was written over a year before Bahá’u’lláh claimed to be a Manifestation of God.
If any slice of the Book of Certitude captures the essence of the book, it is perhaps the following passage about uncertainty, which concerns those Muslims who rejected the Báb on the basis that the Qur’án established that Muhammad was the “Seal of the Prophets”:
“Whoso sayeth ‘why’ or ‘wherefore’ hath spoken blasphemy!” Were these people to shake off the slumber of negligence and realize that which their hands have wrought, they would surely perish, and would of their own accord cast themselves into fire—their end and real abode. Have they not heard that which He hath revealed: “He shall not be asked of His doings?” [Qur’án 21.23] In the light of these utterances, how can man be so bold as to question Him, … ?
This passage declares it a crime (blasphemy) to question any Manifestation of God, or I suppose, any man who claims to be such a mouthpiece of God. If there should be any doubt as to what the word “certitude” meant to Bahá’u’lláh, this prohibition against any expression of doubt ought to help clear things up.