Behold the Lamb [of God.] M. Bridges. [Passiontide.] First published in his Hymns of the Heart, &c, 1848, in 7 stanzas of 7 lines, and entitled "Ecce Agnus Dei." It is found in many modern collections both in Great Britain and in America, but never in a full and correct form. Scarcely two texts can be found alike, whether they begin with the original first line, or as—" Behold the Lamb of God/' as in Hymns Ancient & Modern, Thring, and others….
A comparison of this text with that in any collection will show how far alterations may have been introduced. In addition to being altered, it is usually abbreviated as well. In some American collections, including Dr. Hatfield's Church Hymn Book, 1872, No. 500, a hymn is given as—"Archangels! fold your wings," and attributed to "Samuel Egerton Brydges, 1820, a," which is really a portion of this hymn rewritten, beginning with line 2 of stanza iii.
--Excerpts from John Julian, Dictionary of Hymnology (1907)