From the very commencement of his ministry in Edinburgh, Candlish took the deepest interest in ecclesiastical questions, and he soon became involved as one of the chief actors in the struggle which was then agitating the church. His first Assembly speech, delivered in 1839, placed him at once among the leaders of the party that afterwards formed the Free Church, and his influence in bringing about what is known as the Disruption was inferior only to that of Chalmers. As a debater he had powers of the highest order, which would have won for him a foremost place in any deliberative assembly. Great as was his popularity as a preacher, it was in the ecclesiastical arena that his ability chiefly showed itself, and probably no other single man had from first to last so large a share in shaping the constitution and guiding the policy of the Free Church. He was actively engaged at one time or other in ^nearly all the various schemes of the church, but speciaí mention should be made of his services in the Education Committee, of which he was convener from 1846 to 1863, and in the unsuccessful negotiations for union among the non-established Presbyterian denominations of Scotland, which were carried on during the years 1863-73. In the Assembly of 1861 he filled the moderator’s chair.

As a theologian the position of Candlish was perhaps inferior to that which he held as a preacher and ecclesiastic, but it was not inconsiderable. So early as 1841 his reputation in this department was sufficient to secure for him the nomination to the newly-founded chair of Biblical Criticism in the University of Edinburgh. The appointment was, however, not ratified by the Home Secretary in consequence of a representation made in the House of Lords, by the earl of Aberdeen, that Candlish had set himself in opposition to the law of the land by preaching in the parish of Huntly in spite of an interdict from the Court of Session. By a somewhat curious coincidence a second appointment to a professorship was also nullified, though in this case by his own act, and after a few months’ tenure of the office. In 1847 Candlish, who had received the degree of D.D. from Princeton, New Jersey, in 1841, was chosen by the Assembly of the Free Church to succeed Chalmers in the chair of divinity iu the New College, Edinburgh. After partially fulfilling the duties of the office for one session, he was led to resume the charge of St George’s, the clergyman who had been chosen by the congregation as his successor having died before entering on his work. In 1862 he was again connected with the New College, being appointed principal in succession to Cunningham, with the understanding that he should still retain his position as minister of St George’s. Some months before this he had obtained the assistance of a colleague in his pastoral work,but he continued to preach, with one or two intervals of somewhat protracted illness, until within a short time of his death, which occurred on the 19th October 1873.

Though his greatest power was not displayed through the press, Candlish made a number of somewhat important contributions to theological literature. In 1842 he published the first volume of his Contributions towards ths Exposition of ihs Book of Genesis, a work which was completed in three volumes several years later. In 1854 he delivered, in Exeter Hall, London, a lfecture on the Theological Essays of the Rev. F. D. Maurice, which he afterwards published, along with a fuller examination of the doctrine of the essays. A treatise entitled The Atonement ; its Reality, Completeness, and Extent (1861) was based upon a smaller work which first appeared in 1845. In 1864 he delivered the first series of Cunningham lectures, taking for his subject The Fatherhood of God. Published immediately afterwards, the lectures excited considerable discussion on account of the peculiar views they represented. Further illustrations of these views were given in two works published about the same time as the lectures, one a treatise On ths Sonship and Brotherhood of Believers, and the other an exposition of the first epistle of St John. Among his other works were Life in a Risen Saviour ; Scripture Characters ; Reason and Revelation; and The Christian’s Sacrifice and Service of Praise. A posthumous volume of sermons with a short prefatory biographical sketch appeared in 1874.