Have you on the Lord believed? Fullness of Grace. This hymn arose out of the following circumstances:—"A vast fortune was left in the hands of a minister for one of his poor parishioners. Fearing that it might be squandered if suddenly bestowed upon him, the wise minister sent him a little at a time, with a note saying, “This is thine; use it wisely; there is more to follow.” Hence also the refrain ‘More to follow,’ by which the hymn is known."
-John Julian, Dictionary of Hymnology (1907)