[2] One of his uncles was George Rainy, the noted slave plantation owner and personality involved in the Highland Clearances.

However his interests turned to the church, which had been the path of his grandfather, Rev George Rainy (1734–1810) of Sutherland, in northern Scotland.

He was caught by the evangelical fervour of the Disruption of 1843, and moved to Edinburgh to train as Free Church minister at New College.

He guided it through the controversies as to Robertson Smith's heresies, as to the use of hymns and instrumental music (a large part of the church preferring unaccompanied singing), and also to the Declaratory Act.

[citation needed] The main secular assembly space within New College is now called Rainy Hall.

However, it is still used as a dining hall by New College students and by Commissioners attending the annual General Assembly of the Church of Scotland.