The Proper, True, and Supreme Deity of Our Lord and Saviour Jesus Christ, Proved and Asserted From the Holy Sciptures was written against the unbiblical teaching of John Simson, then a professor in the seminary of the Church of Scotland. It was the failure of the Church to discipline Dr. Simpson that led to the disagreements which eventually formed the Associate Church of the Seceder brethren.
A Presbyterian minister, a man of resolution and daring. He was jocularly called 'the lion of the secession church' by his colleagues. With Erskine, William Wilson, and James Fisher he was joint author of the 'judicial testimony' against the church of Scotland, issued in December 1736.