That City is none other than the Word of God revealed in every age and dispensation. In the days of Moses it was the Pentateuch; in the days of Jesus, the Gospel; in the days of Muhammad, the Messenger of God, the Qur'án; in this day, the Bayan; and in the Dispensation of Him Whom God will make manifest, His own Book -- the Book unto which all the Books of former Dispensations must needs be referred, the Book that standeth amongst them all transcendent and supreme.

(Gleanings from the Writings of Bahá’u’lláh)