Blest is the man, for ever bless'd. I. Watts. [Ps. xxxii.] His L.M. rendering of Ps. xxxii., published in his Psalms of David, &c, 1719, in 4 stanzas of 4 lines. Dr. Watts's note thereupon explains the liberty taken with the Psalm as follows:—
"These two first verses of this Psalm being cited by the Apostle in the 4th chapter of Romans, to shew the freedom of our pardon and justification by grace without works, I have, in this version of it, enlarged the sense, by mention of the Blood of Christ, and faith and Repentance; and because the Psalmist adds. A spirit in which is no guile, I have inserted that sincere obedience, which is scriptural evidence of our faith and justification."
As a hymn in common use in Great Britain it has almost died out; but in America it still survives in a few collections.
-- John Julian, Dictionary of Hymnology (1907)