The Báb was the Herald of the new Revelation. He prepared the peoples for the coming of Him "Whom God will make Manifest". In other words, He did not only have the enormous task of being a Messenger of God but He also prepared His followers (known then as Babis) to be able to recognize the Manifestation of God that would soon make Himself manifest to them.
So, for the Baha'is, the Declaration of The Báb marks the beginning of the Baha'i era. 23rd of May 1844 is when it happened and this is the story of the blessed night related by Mulla Husayn and documented on The Dawn-Breakers: Nabíl’s Narrative of the Early Days of the Bahá’í Revelation, p. 676:
“‘We soon found ourselves standing at the gate of a house of modest appearance. He knocked at the door, which was soon opened by an Ethiopian servant. “Enter therein in peace, secure,”were His words as He crossed the threshold and motioned me to follow Him. His invitation, uttered with power and majesty, penetrated my soul. I thought it a good augury to be addressed in such words, standing as I did on the threshold of the first house I was entering in Shíráz, a city the very atmosphere of which had produced already an indescribable impression upon me. Might not my visit to this house, I thought to myself, enable me to draw nearer to the Object of my quest? Might it not hasten the termination of a period of intense longing, of strenuous search, of increasing anxiety, which such a quest involves? As I entered the house and followed my Host to His chamber, a feeling of unutterable joy invaded my being. Immediately 55 we were seated, He ordered a ewer of water to be brought, and bade me wash away from my hands and feet the stains of travel. I pleaded permission to retire from His presence and perform my ablutions in an adjoining room. He refused to grant my request, and proceeded to pour the water over my hands. He then gave me to drink of a refreshing beverage, after which He asked for the samovar and Himself prepared the tea which He offered me.
Overwhelmed with His acts of extreme kindness, I arose to depart. “The time for evening prayer is approaching,” I ventured to observe. “I have promised my friends to join them at that hour in the Masjid-i-Ílkhání.” With extreme courtesy and calm He replied: “You must surely have made the hour of your return conditional upon the will and pleasure of God. It seems that His will has decreed otherwise. You need have no fear of having broken your pledge.” His dignity and self-assurance silenced me I renewed my ablutions and prepared for prayer. He, too, stood beside me and prayed. Whilst praying, I unburdened my soul, which was much oppressed, both by the mystery of this interview and the strain and stress of my search. I breathed this prayer: “I have striven with all my soul, O my God, and until now have failed to find Thy promised Messenger. I testify that Thy word faileth not, and that Thy promise is sure.”
And he goes on, explaining:
That night, that memorable night, was the eve preceding the fifth day of Jamádiyu’l-Avval, in the year 1260 A.H. It was about an hour after sunset when my youthful Host began to converse with me. “Whom, after Siyyid Kázim,” He asked me, “do you regard as his successor and your leader?” “At the hour of his death,” I replied, “our departed teacher insistently exhorted us to forsake our homes, to scatter far and wide, in quest of the promised Beloved. I have, accordingly, journeyed to Persia, have arisen to accomplish his will, and am still engaged in my quest.” “Has your teacher,” He further enquired, “given you any detailed indications as to the distinguishing features of the promised One?” “Yes,” I replied, “He is of a pure lineage, is of illustrious descent, and of the seed of Fátimih. As to His age, He is more than twenty and less than thirty. He is endowed with innate knowledge. He is of medium height, abstains from smoking, and is free from bodily deficiency.” He paused for a while and then with vibrant voice declared: “Behold, all these signs are manifest in Me!” He then considered each of the above-mentioned signs separately, and conclusively demonstrated that each and all were applicable to His person. I was greatly surprised, and politely observed: “He whose advent we await is a Man of unsurpassed holiness, and the Cause He is to reveal, a Cause of tremendous power. Many and diverse are the requirements which He who claims to be its visible embodiment must needs fulfil. How often has Siyyid Kázim referred to the vastness of the knowledge of the promised One! How often did he say: ‘My own knowledge is but a drop compared with that with which He has been endowed. All my attainments are but a speck of dust in the face of the immensity of His knowledge. Nay, immeasurable is the difference!’” No sooner had those words dropped from my lips than I found myself seized with fear and remorse, such as I could neither conceal nor explain. I bitterly reproved myself, and resolved at that very moment to alter my attitude and to soften my tone. I vowed to God that should my Host again refer to the subject, I would, with the utmost humility, answer and say: “If you be willing to substantiate your claim, you will most assuredly deliver me from the anxiety and suspense which so heavily oppress my soul. I shall truly be indebted to you for such deliverance.” When I first started upon my quest, I determined to regard the two following standards as those whereby I could ascertain the truth of whosoever might claim to be the promised Qá’im. The first was a treatise, which I had myself composed, bearing upon the abstruse and hidden teachings propounded by Shaykh Aḥmad and Siyyid Kázim. Whoever seemed to me capable of unravelling the mysterious allusions made in that treatise, to him I would next submit my second request, and would ask him to reveal, without the least hesitation or reflection, a commentary on the Súrih of Joseph, in a style and language entirely different from the prevailing standards of the time. I had previously requested Siyyid Kázim, in private, to write a commentary on that same Súrih, which he refused, saying: “This is, verily, beyond me. He, that great One, who comes after me will, unasked, reveal it for you. That commentary will constitute one of the weightiest testimonies of His truth, and one of the clearest evidences of the loftiness of His position.”
Incredible! What a blessed night indeed! And what was to follow...
I was revolving these things in my mind, when my distinguished Host again remarked: “Observe attentively. Might not the Person intended by Siyyid Kázim be none other than I?” I thereupon felt impelled to present to Him a copy of the treatise which I had with me. “Will you,” I asked Him, “read this book of mine and look at its pages with indulgent eyes? I pray you to overlook my weaknesses and failings.” He graciously complied with my wish. He opened the book, glanced at certain passages, closed it, and began to address me. Within a few minutes He had, with characteristic vigour and charm, unravelled all its mysteries and resolved all its problems. Having to my entire satisfaction accomplished, within so short a time, the task I had expected Him to perform, He further expounded tome certain truths which could be found neither in the reported sayings of the imáms of the Faith nor in the writings of Shaykh Aḥmad and Siyyid Kázim. These truths, which I had never heard before, seemed to be endowed with refreshing vividness and power. “Had you not been My guest,” He afterwards observed, “your position would indeed have been a grievous one. The all-encompassing grace of God has saved you. It is for God to test His servants, and not for His servants to judge Him in accordance with their deficient standards. Were I to fail to resolve your perplexities, could the Reality that shines within Me be regarded as powerless, or My knowledge be accused as faulty? Nay, by the righteousness of God! it behoves, in this day, the peoples and nations of both the East and the West to hasten to this threshold, and here seek to obtain the reviving grace of the Merciful. Whoso hesitates will indeed be in grievous loss. Do not the peoples of the earth testify that the fundamental purpose of their creation is the knowledge and adoration of God? It behoves them to arise, as earnestly and spontaneously as you have arisen, and to seek with determination and constancy their promised Beloved.” He then proceeded to say: “Now is the time to reveal the commentary on the Súrih of Joseph.” He took up His pen and with incredible rapidity revealed the entire Súrih of Mulk, the first chapter of His commentary on the Súrih of Joseph. The overpowering effect of the manner in which He wrote was heightened by the gentle intonation of His voice which accompanied His writing. Not for one moment did He interrupt the flow of the verses which streamed from His pen. Not once did He pause till the Súrih of Mulk was finished. I sat enraptured by the magic of His voice and the sweeping force of His revelation. At last I reluctantly arose from my seat and begged leave to depart. He smilingly bade me be seated, and said: “If you leave in such a state, whoever sees you will assuredly say: ‘This poor youth has lost his mind.’” At that moment the clock registered two hours and eleven minutes after sunset. That night, the eve of the fifth day of Jamádiyu’l-Avval, in the year 1260 A.H., corresponded with the eve preceding the sixty-fifth day after Naw-rúz, which was also the eve of the sixth day of Khurdád, of the year Nahang. “This night,” He declared, “this very hour will, in the days to come, be celebrated as one of the greatest and most significant of all festivals. Render thanks to God for having graciously assisted you to attain your heart’s desire, and for having quaffed from the sealed wine of His utterance. ‘Well is it with them that attain thereunto.’
At the third hour after sunset, my Host ordered the dinner to be served. That same Ethiopian servant appeared again and spread before us the choicest food. That holy repast refreshed alike my body and soul. In the presence of my Host, at that hour, I felt as though I were feeding upon the fruits of Paradise. I could not but marvel at the manners and the devoted attentions of that Ethiopian servant whose very life seemed to have been transformed by the regenerating influence of his Master. I then, for the first time, recognised the significance of this well-known traditional utterance ascribed to Muḥammad: “I have prepared for the godly and righteous among My servants what eye hath seen not, ear heard not, nor human heart conceived.” Had my youthful Host no other claim to greatness, this were sufficient—that He received me with that quality of hospitality and loving-kindness which I was convinced no other human being could possibly reveal.
He then shares his thoughts and feelings:
I sat spellbound by His utterance, oblivious of time and of those who awaited me. Suddenly the call of the muadhdhín, summoning the faithful to their morning prayer, awakened me from the state of ecstasy into which I seemed to have fallen. All the delights, all the ineffable glories, which the Almighty has recounted in His Book as the priceless possessions of the people of Paradise—these I seemed to be experiencing that night. Methinks I was in a place of which it could be truly said: “Therein no toil shall reach us, and therein no weariness shall touch us”; “No vain discourse shall they hear therein, nor any falsehood, but only the cry, ‘Peace! Peace!’”; “Their cry therein shall be, ‘Glory be to Thee, O God!’ and their salutation therein, ‘Peace!’ And the close of their cry, ‘Praise be to God, Lord of all creatures!’
He then addressed me in these words: “O thou who art the first to believe in Me! Verily I say, I am the Báb, the Gate of God, and thou art the Bábu’l-Báb, the gate of that Gate. Eighteen souls must, in the beginning, spontaneously and of their own accord, accept Me and recognise the truth of My Revelation. Unwarned and uninvited, each of these must seek independently to find Me. And when their number is complete, one of them must needs be chosen to accompany Me on My pilgrimage to Mecca and Medina. There I shall deliver the Message of God to the Sharíf of Mecca. I then shall return to Kúfih, where again, in the Masjid of that holy city, I shall manifest His Cause. It is incumbent upon you not to divulge, either to your companions or to any other soul, that which you have seen and heard. Be engaged in the Masjid-i-Ílkhání in prayer and in teaching. I, too, will there join you in congregational prayer. Beware lest your attitude towards Me betray the secret of your faith. You should continue in this occupation and maintain this attitude until our departure for Ḥijáz. Ere we depart, we shall appoint unto each of the eighteen souls his special mission, and shall send them forth to accomplish their task. We shall instruct them to teach the Word of God and to quicken the souls of men.” Having spoken these words to me, He dismissed me from His presence. Accompanying me to the door of the house, He committed me to the care of God.