自由教会
In 1845, he drew up at the request of the Free church leaders 'A Catechism of the Principles of the Free Church' (1845 and 1848), which involved him in a controversy with the Duke of Argyll. In December 1841, Gray was commissioned to visit Switzerland to express the sympathy of the Free Church with the suspended ministers of the Canton de Vaud; he extended his tour to Constantinople. In 1855, he was appointed convener of the Glasgow evangelisation committee, and he was always active in home missions and in spreading education. Failing health made another long continental tour necessary in 1859. He died at Perth 10 March 1861. He married, 23 July 1834, Barbara, daughter of Alexander Cooper. Robert Smith Candlish collected nineteen of Gray's sermons, with memoir and portrait, under the title 'Gospel Contrasts and Parallels,’ Edinburgh, 1862.