These daily readings have been selected from various sources, chiefly from the lectures given at the Bible Training College, Clapham, during the years 1911-1915; then, from October 1915 to November 1917, from talks given night by night in the Y.M.C.A. Huts, Zeitoun, Egypt. In November 1917 my husband entered into God's presence. Since then many of the talks have been published in book form, and others from which these readings have been gathered will also be published in due course.
via myutmost.org
Oswald Chambers's wife published his devotional book, My Utmost for His Highest, after his death. It has become a world favorite.
We never know what good may come from our efforts after we are gone. God is not limited to our lifespan when he wants to use our works for his kingdom.