'Tis a point I long to know. J. Newton. [In Doubt and Fear.] Appeared in the Olney Hymns, 1779, Bk. i., No. 119, in 9 st of 4 lines. It is in common use in an abbreviated form, and opening with the first line as above. In some collections it begins, "Lord, my God, I long to know"; and in others, "Could my heart so hard remain" (stanza iii.). These altered forms of the text are in use principally in America.
--John Julian, Dictionary of Hymnology (1907)