Bahá’u’lláh  appeared at a time when the Persian Empire was immersed in profound obscurantism and ignorance and lost in the blindest fanaticism.
[1 Jamal-i-Mubarak, the Blessed Beauty, the title which is here given to Bahá'u'lláh. He is also called Jamal-i-Qidam, the Preexistent, or Ancient Beauty. But we shall designate Him as Bahá'u'lláh, the title by which He is known in the West.
In the European histories, no doubt, you have read detailed accounts of the morals, customs and ideas of the Persians during the last centuries. It is useless to repeat them. Briefly, we will say that Persia had fallen so low that to all foreign travelers it was a matter of regret that this country, which in former times had been so glorious and highly civilized, had now become so decayed, ruined and upset, and that its population had lost its dignity.
It was at this time that Bahá'u'lláh appeared. His father was one of the viziers, not one of the 'ulama. As all the people of Persia know, He had never studied in any school, nor had He associated with the 'ulama or the men of learning. The early part of His life was passed in the greatest happiness. His companions and associates were Persians of the highest rank, but not learned men.
As soon as the Báb became manifested, Bahá'u'lláh said, "This great Man is the Lord of the righteous, and faith in Him is incumbent upon all." And He arose to assist the Báb and gave many proofs and positive evidences of His truth, in spite of the fact that the 'ulama of the state religion had constrained the Persian government to oppose and resist Him and had further issued decrees ordering the massacre, pillage, persecution and expulsion of His followers. In all the provinces they began to kill, to burn, to pillage the converts and even to assault the women and children. Regardless of this, Bahá'u'lláh arose to proclaim the word of the Báb with the greatest firmness and energy. Not for one moment was He in concealment; He mixed openly with His enemies. He was occupied in showing forth evidences and proofs and was recognized as the Herald of the Word of God. In many changes and chances He endured the greatest misfortunes, and at every moment He ran the risk of being martyred.
He was put into chains and confined in an underground prison. His vast property and inheritance were pillaged and confiscated. He was exiled four times from land to land and found rest only in the "Greatest Prison." 
[1 Exiled first to Baghdad, then to Constantinople, then to Adrianople, He was imprisoned in 'Akká (Acre), "the Greatest Prison," in 1868.]
In spite of all this He never ceased for one instant His proclamation of the greatness of the Cause of God. He manifested such virtue, knowledge and perfections that He became a wonder to all the people of Persia. So much so that in Tihran, Baghdad, Constantinople, Rumelia, and even in ‘Akká, every one of the learned and scientific men who entered His presence, whether friend or enemy, never failed to receive the most sufficient and convincing answer to whatever question was propounded. All frequently acknowledged that He was alone and unique in all perfections.
It often happened that in Baghdad certain Muhammadan ‘ulama, Jewish rabbis and Christians met together with some European scholars, in a blessed Reunion: each one had some question to propose, and although they were possessed of varying degrees of culture, they each heard a sufficient and convincing reply, and retired satisfied. Even the Persian ‘ulama who were at Karbila and Najaf chose a wise man whom they sent on a mission to Him; his name was Mulla Hasan ‘Amu. He came into the Holy Presence, and proposed a number of questions on behalf of the ‘ulama, to which Bahá’u’lláh replied. Then Hasan ‘Amu said, “The ‘ulama recognize without hesitation and confess the knowledge and virtue of Bahá’u’lláh, and they are unanimously convinced that in all learning he has no peer or equal; and it is also evident that he has never studied or acquired this learning; but still the ‘ulama say, ‘We are not contented with this; we do not acknowledge the reality of his mission by virtue of his wisdom and righteousness. Therefore, we ask him to show us a miracle in order to satisfy and tranquilize our hearts.’”
Bahá’u’lláh replied, “Although you have no right to ask this, for God should test His creatures, and they should not test God, still I allow and accept this request. But the Cause of God is not a theatrical display that is presented every hour, of which some new diversion may be asked for every day. If it were thus, the Cause of God would become mere child’s play.
“The ulamas must, therefore, assemble, and, with one accord, choose one miracle, and write that, after the performance of this miracle they will no longer entertain doubts about Me, and that all will acknowledge and confess the truth of My Cause. Let them seal this paper, and bring it to Me. This must be the accepted criterion: if the miracle is performed, no doubt will remain for them; and if not, We shall be convicted of imposture.” The learned man, Hasan ‘Amu, rose and replied, “There is no more to be said”; he then kissed the knee of the Blessed One although he was not a believer, and went. He gathered the ‘ulama and gave them the sacred message. They consulted together and said, “This man is an enchanter; perhaps he will perform an enchantment, and then we shall have nothing more to say.” Acting on this belief, they did not dare to push the matter further.
[1 The penetrating judgment of Bahá'u'lláh upon this occasion overcame the malignity of His enemies, who, it was certain, would never agree in choosing what miracle to ask for.]
This man, Hasan ‘Amu, mentioned this fact at many meetings. After leaving Karbila he went to Kirmanshah and Tihran and spread a detailed account of it everywhere, laying emphasis on the fear and the withdrawal of the ‘ulama.
Briefly, all His adversaries in the Orient acknowledged His greatness, grandeur, knowledge and virtue; and though they were His enemies, they always spoke of Him as “the renowned Bahá’u’lláh.”
At the time when this great Light suddenly arose upon the horizon of Persia, all the people, the ministers, the ‘ulama and men of other classes rose against Him, pursuing Him with the greatest animosity, and proclaiming “that this man wishes to suppress and destroy the religion, the law, the nation and the empire.” The same was said of Christ. But Bahá’u’lláh alone and without support resisted them all, without ever showing the least weakness. At last they said, “As long as this man is in Persia, there will be no peace and tranquillity; we must banish him, so that Persia may return to a state of quietude.”
They proceeded to use violence toward Him to oblige Him to ask for permission to leave Persia, thinking that by this means the light of His truth would be extinguished, but the result was quite the contrary. The Cause became magnified, and its flame more intense. At first it spread throughout Persia only, but the exile of Bahá’u’lláh caused the diffusion of the Cause throughout other countries. Afterward His enemies said, “‘Iraq-i-’Arab  is not far enough from Persia; we must send him to a more distant kingdom.” This is why the Persian government determined to send Bahá’u’lláh from ‘Iraq to Constantinople. Again the event proved that the Cause was not in the least weakened. Once more they said, “Constantinople is a place of passage and of sojourn for various races and peoples; among them are many Persians.” For this reason the Persians had Him further exiled to Rumelia; but, when there, the flame became more powerful, and the Cause more exalted. At last the Persians said, “Not one of these places is safe from his influence; we must send him to some place where he will be reduced to powerlessness, and where his family and followers will have to submit to the direst afflictions.” So they chose the prison of ‘Akká, which is reserved especially for murderers, thieves and highway robbers, and in truth they classed Him with such people. But the power of God became manifested: His word was promulgated, and the greatness of Bahá’u’lláh then became evident, for it was from this prison and under such humiliating circumstances that He caused Persia to advance from one state into another state. He overcame all His enemies and proved to them that they could not resist the Cause. His holy teachings penetrated all regions, and His Cause was established.
[1 'Iraq; as opposed to that district of Iran known then as 'Iraq-i-A'zam and now called Arak.]
Indeed, in all parts of Persia His enemies arose against Him with the greatest hatred, imprisoning, killing and beating His converts, and burning and razing to the ground thousands of dwellings, striving by every means to exterminate and crush the Cause. In spite of all this, from the prison of murderers, highway robbers and thieves, it became exalted. His teachings were spread abroad, and His exhortations affected many of those who had been the most full of hatred, and made them firm believers. Even the Persian government itself became awakened and regretted that which had arisen through the fault of the ‘ulama.
When Bahá’u’lláh came to this prison in the Holy Land, the wise men realized that the glad tidings which God gave through the tongue of the Prophets two or three thousand years before were again manifested, and that God was faithful to His promise; for to some of the Prophets He had revealed and given the good news that “the Lord of Hosts should be manifested in the Holy Land.” All these promises were fulfilled; and it is difficult to understand how Bahá’u’lláh could have been obliged to leave Persia, and to pitch His tent in this Holy Land, but for the persecution of His enemies, His banishment and exile. His enemies intended that His imprisonment should completely destroy and annihilate the blessed Cause, but this prison was in reality of the greatest assistance and became the means of its development. The divine renown of Bahá’u’lláh reached the East and the West, and the rays of the Sun of Truth illuminated all the world. Praise be to God! though He was a prisoner, His tent was raised on Mount Carmel, and He moved abroad with the greatest majesty. Every person, friend or stranger, who came into His presence used to say, “This is a prince, not a captive.”
Upon His arrival in prison  He addressed an epistle to Napoleon, which He sent through the French ambassador. The gist of it was, “Ask what is Our crime, and why We are confined in this prison and this dungeon.” Napoleon made no reply. Then a second epistle was issued, which is contained in the Suriy-i-Haykal. The epitome of it is: “Oh Napoleon, as thou hast not listened to My proclamation, and as thou hast not answered it, thy dominion will before long be taken away from thee, and thou wilt be utterly destroyed.” This epistle was sent to Napoleon by post, through the care of Cesar Ketaphakou, as was known to all the companions of His exile. The text of this warning reached the whole of Persia, for it was at that time that the Kitáb-i-Haykal was spread in Persia, and this epistle was among the contents of this book. This happened in A.D. 1869, and as this Suriy-i-Haykal was circulated in Persia and India and was in the hands of all believers, they were waiting to see what would come to pass. Not long after, in A.D. 1870, the war between Germany and France broke out; and though no one at that time expected the victory of Germany, Napoleon was defeated and dishonored; he surrendered to his enemies, and his glory was changed into deep abasement.
[2 Napoleon III.]
[3 One of Bahá'u'lláh's works written after His declaration.]
[4 Son of a French Consul in Syria with whom Bahá'u'lláh had friendly relations.]
Tablets  were also sent to other kings, and among them was the letter to H. M. Násiri’d-Dín Sháh. In that epistle Bahá’u’lláh said, “Have Me summoned, gather the ‘ulama, and ask for proofs and arguments, so that the truth and falsehood may become known.” H. M. Násiri’d-Dín Sháh sent the blessed epistle to the ‘ulama and proposed to them that they should undertake this mission, but they dared not do so. Then he asked seven of the most celebrated among them to write an answer to the challenge. After some time they returned the blessed letter, saying, “This man is the opposer of religion and the enemy of the Shah.” His majesty the Shah of Persia was much vexed, and said, “This is a question for proofs and arguments, and of truth or falsehood: what has it to do with enmity to the government? Alas! how much we respected these ‘ulama, who cannot even reply to this epistle.”
[1 Name given to the epistles of Bahá'u'lláh.]
Briefly, all that was recorded in the Tablets to the Kings is being fulfilled: if from the year A.D. 1870 we compare the events that have occurred, we will find everything that has happened has appeared as predicted; only a few remain which will afterward become manifested.
So also foreign peoples, and other sects who were not believers, attributed many wonderful things to Bahá’u’lláh. Some believed that He was a saint, and some even wrote treatises about Him. One of them, Siyyid Davudi, a Sunnite savant of Baghdad, wrote a short treatise in which he related certain supernatural acts of Bahá’u’lláh. Even now, in all parts of the East, there are some people who, though they do not believe in His manifestation, nevertheless believe Him to be a saint and relate miracles attributed to Him.
To sum up, both His antagonists and His partisans, as well as all those who were received in the sacred spot, acknowledged and bore witness to the greatness of Bahá’u’lláh. Though they did not believe in Him, still they acknowledged His grandeur, and as soon as they entered the sacred spot, the presence of Bahá’u’lláh produced such an effect on most of them that they could not utter a word. How many times it happened that one of His most bitter enemies would resolve within himself, “I will say such and such things when I reach His presence, and I will dispute and argue thus with Him,” but when he entered the Holy Presence, he would become amazed and confounded, and remain speechless.
Bahá’u’lláh had never studied Arabic; He had not had a tutor or teacher, nor had He entered a school. Nevertheless, the eloquence and elegance of His blessed expositions in Arabic, as well as His Arabic writings, caused astonishment and stupefaction to the most accomplished Arabic scholars, and all recognized and declared that He was incomparable and unequaled.
If we carefully examine the text of the Torah, we see that the Divine Manifestation never said to those who denied Him, “Whatever miracle you desire, I am ready to perform, and I will submit to whatever test you propose.” But in the Epistle to the Shah, Bahá’u’lláh said clearly, “Gather the ‘ulama, and summon Me, that the evidences and proofs may be established.”
[1 Cf. p. 30, n.1. In giving such importance to this example of the good sense of Bahá'u'lláh, 'Abdu'l-Bahá means to emphasize the uselessness of miracles as a proof of the truth of the Manifestations of God. Cf. "Miracles," p. 100.]
For fifty years Bahá’u’lláh faced His enemies like a mountain: all wished to annihilate Him and sought His destruction. A thousand times they planned to crucify and destroy Him, and during these fifty years He was in constant danger.
In this day Persia is in such a state of decadence and ruin that all intelligent men, whether Persians or foreigners, who realize the true state of affairs, recognize that its progress, its civilization and its reconstruction depend upon the promulgation of the teachings and the development of the principles of this great Personage.
Christ, in His blessed day, in reality only educated eleven men: the greatest of them was Peter, who, nevertheless, when he was tested, thrice denied Christ. In spite of this, the Cause of Christ subsequently permeated the world. At the present day Bahá’u’lláh has educated thousands of souls who, while under the menace of the sword, raised to the highest heaven the cry of “Ya Baha’u’l-Abha”;
[1 A cry used as a declaration of faith by the Bahá'ís, literally, "Oh Thou the Glory of Glories!"]
Finally, we must be just and acknowledge what an Educator this Glorious Being was, what marvelous signs were manifested by Him, and what power and might have been realized in the world through Him
(Abdu’l-Baha, Some Answered Questions, p. 34)