This surprises me. I thought that Baha'i accepted the prophets of the Tanakh
Below are some quotes that represent official positions of the Baha'i Faith regarding the Bible. There are more quotes on the link below, but I omitted the quotes that refer to the NT since I know you are not concerned with it.
From the Writings of 'Abdu'l-Bahá
Know ye that the Torah is that which was revealed in the Tablets to Moses, may peace be upon Him, or that to which He was bidden. But the stories are historical narratives and were written after Moses, may peace be upon Him.
(From a previously untranslated Tablet)
Know ye that the Torah is that which was revealed in the Tablets unto Moses, may peace be upon Him, and in that which He was commanded to do.... The glorious Book, the Mighty Decree, is what was in the Tablets which Moses, upon Him be peace, brought from Mount Sinai, and that which He proclaimed unto the Children of Israel, in accordance with the explicit text of those Tablets.
(From a previously untranslated Tablet)
From Letters Written on Behalf of the Guardian:
...The Bible is not
wholly authentic, and in this respect is not to be compared with the Qur'an, and should be wholly subordinated to the authentic writings of Bahá'u'lláh
. (28 July 1936 to a National Spiritual Assembly)
When 'Abdu'l-Bahá states we believe what is in the Bible, He means in substance. Not that we believe every word of it to be taken literally or that every word is the authentic saying of the Prophet.
(11 February 1944 to an individual believer)
We cannot be sure of the authenticity of any of the phrases in the Old or the New Testament. What we can be sure of is when such references or words are cited or quoted in either the Quran or the Bahá'í writings.
(4 July 1947 to an individual believer)
We have no way of substantiating the stories of the Old Testament other than references to them in our own teachings, so we cannot say exactly what happened at the battle of Jericho.
(25 November 1950 to an individual believer)
From letters written on behalf of the Universal House of Justice:
In studying the Bible Bahá'ís must bear two principles in mind. The first is that many passages in Sacred Scriptures are intended to be taken metaphorically, not literally, and some of the paradoxes and apparent contradictions which appear are intended to indicate this. The second is the fact that the text of the early Scriptures, such as the Bible, is not wholly authentic.
(28 May 1984 to an individual believer)
The Bahá'ís believe what is in the Bible to be true in substance. This does not mean that every word recorded in that Book is to be taken literally and treated as the authentic saying of a Prophet.....
...The Bahá'ís believe that God's Revelation is under His care and protection and that the essence, or essential elements, of what His Manifestations intended to convey has been recorded and preserved in Their Holy Books. However, as the sayings of the ancient Prophets were written down some time later, we cannot categorically state, as we do in the case of the Writings of Bahá'u'lláh, that the words and phrases attributed to Them are Their exact words
(9 August 1984 to an individual believer)
The Bible: Extracts on the Old and New Testaments
Mírza Abú'l-Fadl was praised and recommended by 'Abdu'l-Bahá and has been justifiably called the most learned and erudite Bahá'í scholar16.
Regarding the Old Testament, Fadl said that it contained two types of teaching: a) revelation from God, such as the 10 commandments of Moses, the Psalms of David and the books of the Prophets, and b) historical information, such as the books Joshua, Samuel, Kings and Chronicles "...which contain no statement, sign or hint of being divine speech and therefore should not be considered as revelation."[17]
A Baháí View of the Bible