Sachs' great qualities and small failings forced his vocation upon him: he was destined for the pulpit. The easy stream of his eloquence, his depth of feeling, warmth of conviction, grace of gesture, the charm that he exercised when interpreting the prophets and Agadists, the brilliant wit at his command, the beauty of his voice and his smooth diction—all combined to make him unsurpassed by the best preachers of his time, and his only equal was Mannheimer. When standing in the pulpit, Sachs appeared to be transfigured and oblivious of himself; it seemed as if one of the prophets of God were exhorting the people, or encouraging the despondent by his tidings of an ideal future. Even those of his hearers who did not share his convictions were carried away by his eloquence, and were compelled to yield him a tribute of praise. Sachs, however, was a persuasive speaker not only in the pulpit, but also in ordinary conversation. His speech overflowed with the warmth of the sentiments which filled his heart. His impressive words, which issued from the depths of his being, attracted many faithful adherents to Judaism. Whosoever came into contact with him was drawn into a magic circle, and absorbed somewhat of his convictions. His influence was the greater because he never made an effort to persuade; he simply spoke out what was in him. Nothing was more hateful to him than the display of official dignity, sham devotional fervor, and the pastoral airs copied from Christian clergymen.
In Prague, where he roused the German-speaking inhabitants, both Christians and Jews, to a high pitch of enthusiasm, a happy chance brought him into contact with Rapoport (1840–44), one of the founders of Jewish science. An intimate friendship sprang up between these two men, whose education had been conducted on such different lines, and Sachs was introduced by his friend into the rich domain of Jewish literature, which had hitherto been only in part accessible to him, as his attention had been concentrated on the study of the Holy Scriptures and on classical literature. His talent of vividly perceiving the essential and excellent elements of a subject and storing them in his brain, soon made him master of this new material, and enabled him to impart it to a wide circle in a refined form. But Sachs never became fully acquainted with the dialectics of the Talmud, which was Holdheim's strong point, and this territory remained foreign to him. Though he deeply lamented this deficiency in his knowledge, it was no real defect, for such studies did not accord with the Hellenic side of his nature, and would have blighted the blossoms of his genius. As though destined to counteract the influence of the Jewish German Church, which was to assume form in Berlin, and to become the opposite pole to Holdheim's endless negations, he was elected by the congregation of Berlin as preacher and rabbi. Here, by instilling into the minds of his congregants the same Jewish confidence with which he was inspired, and a feeling of righteous pride in belonging to so ancient, noble, and cultured a race, he succeeded to some extent in curing them of their inclination to Christianity, and the evil habit of imitation to which they had so long been subject. This change in thought, which affected the most remote circles, weakened the antipathy towards the Jews of Berlin, which since the time of Friedländer had prevailed in other communities. Sachs was included among the most distinguished personages of the Prussian capital; the cultured Christian world lavished attentions on him, although he did not seek them. Had he given vigorous and energetic effect to his words, and created permanent institutions—for which plenty of opportunity would have been given him by the liberal Berlin community—perhaps the reform congregation might not have arisen.
He combated the reform tendency with all his strength. In Holdheim and his allies he beheld only perverters of Judaism and false leaders of the people, and he openly expressed this opinion, for, as he often remarked, "Against insult and harsh words I am hardened and indifferent." From the pulpit he wielded the scourge of his annihilating scorn against the Jewish German Church, which had so limited the development of Judaism, that it could be contained in a nutshell. But even his opponents admitted that he employed only honorable weapons, the use of others being at variance with his noble nature. He did great harm to the Reform Temple. Persons who had heard Sachs' sermons were wearied by those in the reform synagogue. A comparison between Sachs and his opposite, Holdheim, who was a contrast to him in every way, always resulted in favor of the former. Whilst the Temple where Holdheim preached became more and more deserted, the synagogue in which Sachs officiated became more crowded week after week.
As Sachs performed great services in elevating and strengthening Jewish self-respect, so also he promoted Jewish knowledge. His contributions to the latter touch the form rather than the essence. In fact, he merely popularized Jewish subjects, and rendered them accessible to educated Christians. Sachs did not indeed promulgate novel, epoch-making truths, or discover new facts. Nor was he a poetical artist who could create brilliant pictures of ideal worlds. There was more poetry in his life and teachings than in his verses. His refined perceptions enabled him to recognize and reproduce the slightest shades in the beauties which other artists had created, and he idealized what other inquirers had discovered. The most decided bent of his intellect was towards the exegetical interpretation of Holy Writ. His fervent love of Judaism and its ancient scriptures, his profound knowledge of Hebrew, which was the language of his heart, and finally his delicate æsthetic feeling for philology, were all displayed in his exegetical work. Early in life Sachs conceived the idea, to which he ever remained true, of restoring to the Hebrew Scriptures their pure and original sense, and freeing them from all accretions and blemishes. Inspired by the example of Rückert, "the poet of the East and West, the learned master in translation and exposition," he commenced with the Psalms, which might have been the outpourings of his own pious heart. Afterwards, assisted by various fellow-workers, Sachs translated several books of Holy Scripture in an admirable style to form a "Bible for Israelites." But as he worked more with his heart than his brain, his biblical exegesis was wanting in a firm basis. The task of opening up new paths in this direction fell to the lot of Christian scholars.
Sachs took an active part in excavating the buried figures of the Jewish past, cleansing them from disfiguring incrustations, and placing them in their proper light. Three periodicals were particularly devoted to this purpose—the "Kerem Chemed" and the "Zion" in Hebrew, and the "Orient" in German. Young and old assisted in erecting a Jewish temple of fame, and contributions flowed in from all parts of Europe. The "forties" were especially prolific in the cultivation of Jewish science. It was not pedantic scholarship, but their heart that urged Jewish authors to bring forward clear proof that Judaism, in all its ramifications, went hand in hand with civilization. The Judæo-Spanish epoch exercised special attraction upon Jewish inquirers. It showed what the Jews had accomplished, and could accomplish in wealth of thought and beauty of form. Jewish science at the same time was to serve as an apology to the detractors of Jews and Judaism, and as an ideal for arousing emulation. The brilliant Spanish epoch was known to Jewish scholars alone, and to them only in rough fragments. Sachs undertook to reconstruct from these fragments an organic, beautiful whole, and by his eloquent language to attract those who had no religious interest in the subject. His "Religious Poetry of the Jews in Spain" (1845) offers more than the title indicates. Sachs attractively describes the series of the products of Jewish genius, from the time "when in terrible agony the limbs were torn from the living body," after the destruction of the Jewish center by the Romans, until the flourishing period of neo-Hebraic poetry in Spain. The attention of the cultured world was directed by Sachs' work to the wealth and beauty of Jewish literature in the Middle Ages, of which hitherto it had had no suspicion; even Heine was seized with admiration, and employed his golden pen in its cause.
At the same time the literature of the mediæval Jews in France and Germany, and of the Jewish poets of Provence was treated with copious detail, but in a style fitted for a learned audience. Zunz, the author of this work, justly rebuked his contemporaries for their contemptuous neglect of this branch of literature, to which Christian students of the sixteenth and seventeenth centuries had devoted so much attention.
Continuous devotion to the literature of the Middle Ages threatened to become too one-sided. That epoch, with its productions, was after all only the offspring of the national activity of bygone days, and the grandchild or great-grandchild of a still more important period. This obscure question, the dual origin of Judaism, from the Bible and the Talmud, was clearly illumined by the light of investigation through Jewish science in the "forties." The Talmud lay under a ban, and was treated with most offensive contempt. It was the scapegoat upon which all the guilt and misery of the Jews were laid. Like a leper it was shunned by respectable investigators. But this did not last; the question was raised whether the very writings which had served as the basis for Christianity had not been inter-penetrated with Talmudic elements. The proof of the affirmative answer to this question was boldly undertaken by Frankel. Yet more important was the fact that it was made apparent that the strong side of the Talmud lies in its ideas of justice and their development. The superiority of the Talmudic penal code over the legislation of ancient times was established. The result of a scientific treatment of the Talmud was that Judaism had no cause to be ashamed of it.
But Judaism, together with its followers, remained an undecipherable hieroglyphic, a dark mystery, which one century transmitted to the other unsolved, so long as the "original rock from which it had been hewn, the depths from which it had been hollowed" continued to be unknown. Only a thorough knowledge of its primary sources, its sacred scriptures, could supply the key to this riddle. Centuries had elapsed, and the solution was not yet found. After Holy Writ, the mother of two or three religions, had so long been deified by the masses that it was regarded as "the all in all," and its explanations of life, nature, and history had been eagerly accepted, it had fallen into contempt since the middle of the eighteenth century. It shared the fate of the Jewish race. The rationalistic school indeed paid a good deal of attention to Hebrew sources, but only with the intention of diminishing their value. Eichhorn, Gesenius, Von Bohlen, De Wette, and Tuch were filled with antipathy to the Jews, and were thereby hindered from arriving at a correct understanding of the Old Testament. The clericals Tholuck and Hengstenberg sought vainglory therein, and what they discovered they claimed for Christianity. In Jewish circles there were only three men who occupied themselves in a scientific manner with the exposition of the Scriptures, namely, Krochmal, Luzzatto, and Sachs; but they were timid, they feared pressing too close to the borders of Sinai. A man of childlike mind was the first to raise the veil, to comprehend the language of the Prophets and Psalmists, and to reveal the ancient history of the Jewish people in its true light. With the appearance of "The Prophets of the Old Testament," and "The History of the People of Israel" (1843–1847) by Heinrich Ewald, a new path was opened up for the comprehension of the Hebrew genius and people. The riddle so long obscured approached its solution by the discovery of the key.
"The nations of antiquity, the Babylonians, Indians, Egyptians, Phœnicians, Greeks, and Romans, each under favorable circumstances, pursued only one particular object, till at length they reached an eminence not attained by later generations.... The people of Israel, on the other hand, from the beginning of its historical consciousness, has so clearly kept in view its ultimate goal, and so strongly striven to attain it, that it could not lose it from sight for any length of time, and after any momentary pause it pursued it only the more perseveringly. Its goal is perfect religion.... The history of this ancient people is the history of true religion showing every stage of development up to perfection."
This new promising school has, as its fundamental idea, that the race which owed its origin to the seed of Abraham is actually and truly a "people of God," that has given the world truths of salvation in abundance. The unfolding of these truths is manifested in the course of the history and in the literature of the Israelites. It is certainly a grave error of this school, the first to unravel the artistic web, to imagine that the last page of the history of God's people was written eighteen centuries ago, and that since that period it has only led a shadowy existence. Great memories bring about resurrections, and what people has a grander or more brilliant past than the Jewish, or Israelite, or Hebrew people? But if this people is still to accomplish work in the world's history, its chains must be removed, not only those which weigh down the limbs, but also those which confine the mind. The nation had to be freed, only then was it possible to find out whether it would continue an independent existence, or whether it would succumb in the conflict of races.