Wilt Thou forgive that sin when I began. John Donne. [Lent.] Concerning this hymn, to which special reference is made in the article on Early English Hymnody, Izaak Walton says, in his Life of Donne, after quoting the hymn in detail:—
"I have the rather mentioned this hymn for that he caused it to be set to a most grave and solemn tune, and to be often sung to the organ by the Choristers of St. Paul's [Cathedral] Church in his own hearing, especially at the evening service, and at his return from his customary devotions in that place, did occasionally say to a friend, 'the words of this hymn have restored to me the same thoughts of joy that possessed my soul in my sickness, when I composed it. And, O the power of Church-music! that harmony added to this hymn has raised the affections of my heart, and quickened my grace of zeal and gratitude; and 1 observe that I always return from paying this public duty of prayer and praise with an unexpressible tranquillity of mind, and a willingness to leave the world.'"—Walton's Lives, 1670.
The special sickness during which this hymn was composed fell upon the author during the earlier part of his life. It was sung at St. Paul's Cathedral, at intervals from 1621 to 1631, when Donne died. It was published subsequently in Donne's Poems in 1633; again in 1635, and in later editions, and is usually entitled, "A Hymn to God the Father." Original text in Walton's Lives, 1670 (1850, pp. 53-4).
--John Julian, Dictionary of Hymnology (1907)