The Kitáb-i-Aqdas
Notes
155.Take heed lest ye be prevented by aught that hath been recorded in the Book from hearkening unto this, the Living Book   ¶134
The “Book” is the record of the revealed Word of the Manifestations of God. The “Living Book” is a reference to the Person of the Manifestation.
These words contain an allusion to a statement of the Báb in the Persian Bayán about the “Living Book,” which He identifies as Him Whom God will make manifest. In one of His Tablets Bahá’u’lláh Himself states: “The Book of God hath been sent down in the form of this Youth.”1
In this verse of the Aqdas, and again in paragraph ¶168 of the Aqdas, Bahá’u’lláh refers to Himself as the “Living Book.” He cautions the “followers of every other Faith” against seeking “reasons in their Holy Books” for refuting the utterances of the “Living Book.” He admonishes the people not to allow what has been recorded in the “Book” to prevent them from recognising His Station and from holding fast to what is in this new Revelation.
 
1 Gleanings from the Writings of Bahá’u’lláh, p. 104, LII