The author of "Bench and Bar in Massachusetts", who was in college with him, says of him: "During the five years of his practice at the Middlesex Bar he underwent such an initiation into the profession as no other county could furnish. Shrewdness, energy, resource, strong nerves and mental muscles were needed to ward off the blows which the trained gladiators of this bar were accustomed to inflict. With the lessons learned at the Middlesex Bar he removed to Boston in 1847, where he became associated with the Honorable Joseph Bell, the brother-in-law of Rufus Choate, and began a career almost phenomenal in its success. His management of cases in court was artistic. So well taken were the preliminary steps, so deeply laid was the foundation, so complete and comprehensive was the preparation of evidence and so adroitly was it brought out, so carefully studied and understood were the characters of jurors,--with their whims and fancies and prejudices,--that he won verdict after verdict in the face of the ablest opponents and placed himself by general consent at the head of the jury lawyers of the Suffolk Bar." Adjectives less ambiguous and more uncomplimentary than "shrewd" were also applied to him, and his manner of dominating his juries did not always call forth praise from his contemporaries. In one of the newspaper obituaries at the time of his death it is admitted that he had been "charged with resorting to tricks unbecoming the dignity of a lawyer," but the writer adds that it is an open question if some, or indeed all of them were not legitimate enough, and might not have been paralleled by the practices of some of the ablest of British and Irish barristers. Both in law and in business--for he had important commercial interests--he had prospered. He was rich and a man of the world. Boston, although critical, had not found it unnatural that he should make himself talked about in his conduct of jury trials; but the conspicuousness of his conversion was of another sort: it offended against good taste, and incurred for him the suspicion of hypocrisy.
For, with that ardor and impetuosity which seem always to have made half measures impossible to him, Mr. Durant declared that so far as he was concerned, the Law and the Gospel were irreconcilable, and gave up his legal practice. A case which he had already undertaken for Edward Everett, and from which Mr. Everett was unwilling to release him, is said to be the last one he conducted; and he pleaded in public for the last time in a hearing at the State House in Boston, some years later, when he won for the college the right to confer degrees, a privilege which had not been specifically included in the original charter.
His zeal in conducting religious meetings also offended conventional people. It was unusual, and therefore unsuitable, for a layman to preach sermons in public. St. Francis and his preaching friars had established no precedent in Boston of the 'sixties and 'seventies, and indeed Mr. Durant's evangelical protestantism might not have relished the parallel. Boston seems, for the most part, to have averted its eyes from the spectacle of the brilliant, possibly unscrupulous, some said tricky, lawyer bringing souls to Christ. But he did bring them. We are told that "The halls and churches where he spoke were crowded. The training and experience which had made him so successful a pleader before judge and jury, now, when he was fired with zeal for Christ's cause, made him almost irresistible as a preacher. Very many were led by him to confess the Christian faith. Henry Wilson, then senator, afterwards vice president, was among them. The influence of the meetings was wonderful and far-reaching." We are assured that he "would go nowhere unless the Evangelical Christians of the place united in an invitation and the ministers were ready to cooperate." But the whole affair was of course intensely distasteful to unemotional people; the very fact that a man could be converted argued his instability; and it is unquestionably true that Boston's attitude toward Mr. Durant was reflected for many years in her attitude toward the college which he founded.