William Graham Scroggie (1907-1916)
Known as one of the greatest British Expositors, Scroggie pastored Bethesda from April 1907 to July 1916. Bethesda was Scroggie's third church, having been turned out of his previous two churches because of his stance against modernism and liberalism in the church. Scroggie would go on to pastor Charlotte Chapel, and later the Metropolitan Tabernacle.
A biographical account of Scroggie (Page 16-19 features his time at Bethesda)
Scroggie's greatest known work is the Unfolding Drama of Redemption. Many of his books can be purchased online.