Subsequently he took a leading part in promoting the union of the Presbyterian churches of New South Wales, and was elected Moderator of the third General Assembly in 1867.
In 1869 he was adjudged guilty of contempt of court for having published a letter from a missionary exposing the evils of the Polynesian labour traffic, and which it turned out had reference to the proceedings of a captain who was awaiting trial for the murder of kidnapped South Sea Islanders.
[2] The Chief Justice, Sir Alfred Stephen, dissented from the decision, and Steel was the object of much popular sympathy, evidenced by addresses and presentations.
In the same year Steel visited the New Hebrides, in the Dayspring, in order to see the working of the missions, in which he had always taken a deep interest, and published a book on the subject in 1880.
[2] Amongst other works, Steel is author of the following: Doing Good, or the Christian in Walks of Usefulness (1858); Samuel the Prophet, and the Lessons of his Life and Times (1860); Lives made Sublime by Faith and Work (1861); Burning and Shining Lights, or Memoirs of Good Ministers of Jesus Christ (1864); The Christian Teacher in Sunday Schools (1867); The Shorter Catechism with Analyses, Illustrations, and Anecdotes (1885); and The Achievements of Youth (1891).