April 16

It is clear and evident that the object of all preceding Dispensations hath been to pave the way for the advent of Muhammad, the Apostle of God. These, including the Muhammadan Dispensation, have had, in their turn, as their objective the Revelation proclaimed by the Qá’im. The purpose underlying this Revelation, as well as those that preceded it, has, in like manner, been to announce the advent of the Faith of Him Whom God will make manifest. And this Faith— the Faith of Him Whom God will make manifest— in its turn, together with all the Revelations gone before it, have as their object the Manifestation destined to succeed it. And the latter, no less than all the Revelations preceding it, prepare the way for the Revelation which is yet to follow. The process of the rise and setting of the Sun of Truth will thus indefinitely continue — a process that hath had no beginning and will have no end. 
(The Báb, excerpt from the Persian Bayán, quoted by Shoghi Effendi in a letter dated February 8, 1934; ‘The Dispensation of Baha’u’llah’)