Of justice and of grace I sing. I. Watts. [Psalms ci.] Published in his Psalms of David, 1719, p. 258, in 6 stanzas of 4 lines. It is in use in its original form, and as, "Mercy and judgment I will sing," in the Islington Psalms & Hymns, 1862, and as, "Mercy and judgment will I sing," in the Wesleyan Hymn Book, 1875. Although found in these three forms its use is limited.
--John Julian, Dictionary of Hymnology (1907)