Following the natural inclination of his mind, young Arthur began the study of law, supporting himself by teaching and by preparing boys for college.  It so happened that two years after he was the preceptor of an academy at North Pownal, Vermont, a student from Williams College, named James A. Garfield, came there and taught penmanship in the same academy for several months.

In 1853, young Arthur went to New York City, by the invitation of the Honorable Erastus D. Culver, whose acquaintance he had made when that gentleman represented the Washington County district, and Dr. Arthur was the pastor of the Baptist Church at Greenwich.  Mr. Culver had been noted in Congress as an advanced, anti-slavery man, and he was prompted to take an interest in the son of a clergyman-constituent, who did not fear to express anti-slavery sentiments, at a time when the occupants of pulpits were generally so conservative that they were dumb upon this important question.  Before the close of the year, young Arthur displayed such legal ability and business tact, that he was admitted into partnership, and became a member of the firm of Culver, Parker, and Arthur.  The firm had numerous clients, and the junior partner soon became a successful practitioner, uniting to a thorough knowledge of the law a vigorous understanding and an untiring industry which gained for him an enviable reputation.

Among other cases on the docket of Culver, Parker, and Arthur, was one known as the Lemon slave-case.  A Virginian named Jonathan Lemon undertook to take eight slaves to Texas on steamers, by the way of New York.  While in that city a writ of habeas corpus was issued, and the slaves were brought into the court before Judge Elijah Paine; Mr. Culver and John Jay appearing for the slaves, while H.D.  Lapaugh and Henry L. Clifton were retained by Lemon.  Judge Paine, after hearing long arguments, declared that the fugitive slave law did not apply to slaves who were brought by their masters into a free State, and he ordered their release.  The Legislature of Virginia directed the attorney-general of that State to employ counsel to appeal from Judge Paine’s decision to the Supreme Court of the State of New York.  Mr. Arthur, who was the attorney of record in the case for the people, went to Albany, and after earnest efforts procured the passage of a joint resolution, requesting the governor to employ counsel to defend the interests of the State.  Attorney-General Hoffman, E.D.  Culver, and Joseph Blunt were appointed by the governor as counsel, and Mr. Arthur as the State’s attorney.  The Supreme Court sustained Judge Paine’s decision.  The slave-holder, unwilling to lose his “property,” then engaged Charles O’Conor to argue the case before the State Court of Appeals.  There the counsel for the State were again successful in defending the decision of Judge Paine, and from that day no slave-holder dared to bring his slaves into the city of New York.