Norman Winter, a BBC Radio 4 producer, asked me present three Radio 4 short programmes in July 1997 on my three favourite books the Henry Martyn Library. This is my script of the third one, on Archbishop David Gitari's book, In Season and Out of Season: Sermons to a Nation (Oxford: Regnum, 1996). It was broadcast on 26 July 1997.

This is an edited version of an address given at the Partners in World Mission conference, Swanwick, on 4 November 2015, and was first published on the Covenant website, 2 December, 2015.