Mendelssohn now held so high a position in public opinion, that every new publication bearing his name was eagerly read. The fundamental thought of the preface to Manasseh ben Israel's "Vindication," that religion has no rights over its followers and must not resort to compulsory measures, struck its readers with astonishment. This had never occurred to any Christian believer. Enlightened Christian clergymen, such as Teller, Spalding, Zollikofer, and others, gradually fell in with the new idea, and tendered its originator public applause. Bigoted clerics and obdurate minds, on the other hand, beheld therein the destruction of religion. "All this is new and difficult; first principles are denied," said they. In Jewish circles also many objections were made to Mendelssohn's view. It seemed as if he had suddenly discarded Judaism, which certainly owns an elaborate system of penalties for religious crimes and transgressions. From the Christian camp a pamphlet called "Inquiry into Light and Truth" was launched against him, which asserted that he had finally dropped his mask; that he had embraced the religion of love, and turned his back upon his native faith, which execrates and punishes.
A second time Mendelssohn was compelled to emerge from his retirement, and give his views upon religion. This he did in a work entitled "Jerusalem," or "Upon Ecclesiastical Power and Judaism" (spring, 1783), whose purity of contents and form is a memorial of his lofty genius. The gentleness that breathes through this book, the warmth of conviction, the frankness of utterance, its childlike ingenuousness, yet profoundly thoughtful train of ideas, the graceful style which renders even dry discussion enjoyable—all these qualities earned contemporary approval for this work, and will always assure it a place in literature. At the time it excited great surprise. It had been believed, that, owing to his ideas upon religion and Judaism, Mendelssohn, if he had not entirely broken away from Judaism, had yet declared many things therein to be worthless. He now showed that he was an ardent Jew, and would not yield a tittle of existing Judaism, either rabbinical or biblical; that he, in fact, claimed the highest privileges for it. All this was in accord with his peculiar method of thought.
Judaism recognizes the freedom of religious convictions. Original, pure Judaism, therefore, contains no binding articles of belief, no symbolical books, by which the faithful were compelled to swear and affirm their incumbent duty. Judaism prescribes not faith, but knowledge, and it urges that its doctrines be taken to heart. In this despised religion everyone may think, opine, and err as he pleases, without incurring the guilt of heresy. Its right of inflicting punishment begins only when evil thoughts become acts. Why? Because Judaism is not revealed religion, but revealed legislation. Its first precept is not, "thou shalt believe or not believe," but, "thou shalt do or abstain from doing."
"In the divinely-ordained constitution, state and religion are one. Not unbelief, false teaching, and error, but wicked offenses against the principles of the state and the national constitution are chastised. With the destruction of the Temple, i. e., with the downfall of the state, all corporal and capital punishment, as well as money fines, ceased. The national bonds were dissolved; religious trespasses were no longer crimes against the state, and religion, as such, knows no punishments."
For those who seriously or jestingly had reported that Mendelssohn had separated from Judaism, he laid stress upon two points not wholly germane to his subject, viz., that the so-called ceremonial law of Judaism is likewise, indeed particularly, of divine origin, and that its obligatory character must continue "until it pleases the Supreme to abrogate it as plainly and publicly as it was revealed."
The effect of this detailed apology was greater than Mendelssohn could have expected. Instead of defending himself he had come forward as an accuser, and in a manner at once gentle and forcible he had laid bare the hateful ulcers of the church and state constitution. Two authoritative representatives of the age pronounced flattering opinions upon him and the subject which he was discussing. Kant, who had already testified to his greatness of thought, wrote that he had read "Jerusalem" with admiration for its keenness of argument, its refinement, and cleverness of composition.
"I consider this book the herald of a great reform, which will affect not alone your nation, but also others. You have succeeded in combining your religion with such a degree of freedom of conscience as was never imagined possible, and of which no other faith can boast. You have, at the same time, so thoroughly and clearly demonstrated the necessity of unlimited liberty of conscience in every religion, that ultimately our Church will also be led to reflect how to remove from its midst everything that disturbs and oppresses conscience, which will finally unite all men in their view of the essential points of religion."
Michaelis, the rationalistic anti-Semite, stood baffled, embarrassed, and ashamed before the bold ideas of the "Jerusalem." Judaism, which he had scornfully disdained, now fearlessly and victoriously raised its head. The Jew Mendelssohn, whom he would not have trusted with a penny, appeared the incarnation of conscientiousness and wisdom. Michaelis was sorely perplexed in passing judgment upon this remarkable work. He was obliged to admit many things. Thus, without selfish motives, impelled only by circumstances, Mendelssohn glorified Judaism, and shook off disgrace from his people. In the meantime Dohm was aiding him. He continued to expound Judaism in the most favorable light, and refute all objections, the honest as well as the malicious ones; he had come to regard the quarrel as his own. But Dohm effected most by enlisting through his writings in favor of Jews the sympathies of Mirabeau, a man with shoulders strong enough to bear a new system of the world, and he continued the work of Dohm.
At the same time, and in the same way, that is, indirectly, Mendelssohn again urged the internal rejuvenescence of the Jews, which was to accompany their emancipation. From modesty or discretion, he would not come to the front; he had stimulated Dohm to do battle for their emancipation, and for their regeneration he brought forward another friend, who appeared born for the task. Owing to Mendelssohn, Wessely became a historical personage, who worked with all his energy for the improvement of the Jews, completing the deficiency of Mendelssohn's retiring character. Hartwig (Hartog, Naphtali-Herz) Wessely (born in Hamburg, 1725; died in the same town, 1805) was of a peculiar disposition, combining elements not often associated. His grandfather had established a manufactory for arms in Holstein, and had been a commercial councilor and royal resident. His father also conducted an important business, and had frequent intercourse with so-called great people. In this way Hartwig Wessely came with his father to Copenhagen, where a Portuguese congregation, and also a few German Jews had settled. His early education was the same as that of most boys of that time; he learnt to read Hebrew mechanically, and to mis-translate the Bible, to be launched, a boy of nine, into the labyrinth of the Talmud. But a traveling grammarian, Solomon Hanau, promoted the development of the germs within him, and inspired him with love for the Hebrew language. His labor was not in vain. The seed sown by Hanau was to bear thousand-fold fruit. Wessely's chief interest was the study of the Holy Writings in the original tongue; it was the aim of his life to understand them from all points of view. Owing to his father's frequent contact with non-Jewish circles, in the course of business, Wessely obtained an insight into actual life, and absorbed other branches of knowledge, the modern languages, geography, history, descriptions of travels. These only served as auxiliary sciences to be employed in his special study of the Scriptures, and by their means to penetrate deeper into their thought and spirit. Like Mendelssohn, Wessely was self-taught. Very early he developed taste, a sense for beauty, feeling for purity of speech and form, and repugnance to the mixed dialects and the jargon commonly used among German Jews.
Wessely again resembled Mendelssohn in character, distinguished as he was by strict conscientiousness and elevated feelings of honor. In him, too, thoughts, sentiments, words, and deeds, showed no discrepancy. He was of deep, pure piety, an unswerving adherent to Judaism. His nature, however, did not display the gentle pliancy of Mendelssohn's. He was stiff and pedantic, more inclined to juggle with words and split hairs than to think deeply, and he had no correct idea of the action of world-moving forces. All his life Wessely remained a visionary, and saw the events of the real world through colored glasses. In one way Wessely was apparently superior to Mendelssohn; he was a poet. In reality, however, he only possessed uncommon facility and skill in making beautiful, well-sounding verses of blameless refinement, of graceful symmetrical smoothness, and accurate construction.