Twice every Sunday he usually filled his pulpit in the Tron Church; and when latterly, in St. John's, he had the Rev. Edward Irving as his assistant, the two supplied two pulpits--the parish church and a chapel of ease--while other engagements were often undertaken in various parts of the country. But the work of the pulpit could hardly be reckoned as the chief of Dr. Chalmers's labours. His regard for the old parochial economy of the Kirk of Scotland was a supreme feeling; he looked on every minister as having charge of the people of the parish, and held that it was his duty to watch over their spiritual condition. It was his sense of the infinite importance of this, if Christianity was to retain any hold on the people of our cities, that had made him such an enemy of pluralities, and that roused his intense opposition to the settlement of Dr. Duncan Macfarlane as minister of the High Church of Glasgow, while he retained the office of Principal of the University. He knew for certain that the result would be the almost total neglect of a parish of upwards of ten thousand souls.
The population of the Tron parish was between eleven and twelve thousand. Dr. Chalmers never devoted himself to the regular visitation of the extra-parochial families that formed, to a large extent, his ordinary congregation; where there was sickness or death, he would visit them, but not in ordinary circumstances. His concern was with the people of the parish. His first object was to ascertain their general condition, and for this purpose he determined on a house-to-house visitation. It was a Herculean task. He could but spend a few minutes in each house, give a kindly greeting, put a few questions, perhaps utter an earnest word of Christian counsel, and then invite the inmates to the place where an evening service would be held for the benefit of all. And on the whole it was a depressing task; for he found that a great proportion of the people had no seats in any place of worship, and were in deep ignorance on the high matters of faith and eternity. He had his plans of reformation in readiness, but these involved the enlistment and training of a large body of helpers. As a first step in this direction, on, 20th December 1816, he ordained a few younger men to the office of the eldership, calling on them very earnestly to eschew the example set by many elders around them, who attended only to things temporal, and to devote themselves, by household visitation and other means, to the superintendence of the spiritual interests of their districts. So earnestly was he devoted to the welfare of his parish, that sometimes, when his family were in the country, he would live in a humble room, at a rent of six shillings a week, in order to be near his work; at other times he would dine in the little vestry-room attached to his church.
Next, to meet the alarming ignorance of spiritual truth, he instituted a Sabbath Evening School Society, and got a few members of his congregation to work it. At the end of two years, upwards of two thousand children were under instruction by this means. 'Our meetings,' says one of the members, 'were very delightful. I never saw any set of men who were so animated by one spirit, and whose zeal was so steadily sustained. The Doctor was the life of the whole. He was ever most ready to receive a hint or suggestion from the youngest or most inexperienced member; and if any useful hint came from such a one, he was careful to give him the full merit of it, generally by his name. Although we had no set forms of teaching, we consulted over all the modes, that we might find the best.'