In 1796, he preached his first sermon, and removed to Newark-on-Trent as assistant to Thomas Cooper, as Wesleyanpreacher. In 1796, he entered the Methodist itinerancy, and was received into full connection as a travelling minister in 1801. Meantime, he stationed at Ashby-de-la-Zouch, Castle Donington, and Derby. In 1801, he married Mary Henshaw of Castle Donington. They had two children. In 1803, he withdrew from the Wesleyan connection, and joined the Methodist New Connection, resenting an unfounded charge of Arianism. In 1805, he became assistant secretary of its conference, and in 1807 he was fully admitted to its ministry and was appointed secretary. He was first stationed at Stockport, then from 1806 at Liverpool, where he engaged in literary work for Thomas Kaye. In 1807, he resigned his ministry. In 1808 he was engaged as editor of the Liverpool Courier by Kaye. In 1812 he then returned to the Wesleyan body, and was reinstated in his former position. In 1812, he was stationed at Wakefield, and at Hull from 1814 to 1816. In 1813, Watson drew up a plan of a general missionary society, which was accepted by the conference. In 1810 he was removed to London, and made one of the two general secretaries to the Wesleyan Missionary Society from 1821 to 1827. After holding an appointment at Manchester, from 1827 to 29, he returned to London. He was again appointed a resident secretary to the missionary society from 1832 to 1833.
Death
Watson died in London on 8 January 1833. He was buried in the graveyard behind City Road Chapel, London.
Theology
Watson was a strong Methodist, but constantly wrote of the Anglican communion as "the mother of us all". He was deeply attached to the Anglican prayer-book, and was anxious to keep Methodism in friendly relations with the establishment. Watson was a gifted writer and theologian. In doctrine, is known to be "an orthodox Trinitarian and an Evangelical Arminian". In 1818 he wrote a reply to Adam Clarke's doctrine of the eternal Sonship of Christ; Watson believed that Clarke's views were unorthodox and, therefore, not faithfully Wesleyan. From 1823 to 1929 he worked on his Theological Institutes, which remained a systematic theology standard for many years and deservedly ranks among the ablest expositions of the Arminian system. It was the first attempt to systematize John Wesley's theology and, by extension, Methodist doctrine. His Biblical and Theological Dictionary is more comprehensive than previous attempts in English. In 1831, he wrote also a well-regarded Life of Rev. John Wesley. In Britain, Watson was a leading opponent of slavery. He was not, however, for immediate emancipation.
