O day, most calm, most bright. G. Herbert. [Sunday.] Appeared in The Temple, 1633, as the poem for "Sunday." In Herbert's Life, by Izaak Walton, the fifth stanza is thus referred to:—
"The Sunday before his death he rose suddenly from his bed, or couch, called for one of his instruments, took it into his hand, and said:—
"'My God, my God,
My music shall find Thee,
And every string
Shall have his attribute to sing."
And, having tuned it, he played and sung:—
"The Sundays of man's life.'"
Although this piece is really a poem rather than a hymn, it is included in a few collections, including the Hymnal appended to An Order of Prayer for Use in the Royal College of St. Peter, Westminster, &c, 1889.
--John Julian, Dictionary of Hymnology, New Supplement (1907)