Lord, when Thou didst Thyself undress. H. Vaughan. [Passiontide.] Published in his Silex Scintillans; or, Sacred Poems, &c, Pt. i., 1650, and again in the reprint by the Rev. H. F. Lyte, 1846 (1858 ed., p. 46), in 5 stanzas of 4 lines, and entitled “The Incarnation and Passion." In its complete form it is not found in modern hymnals, but stanzas iv. and v., as "Ah, my dear Lord, what could'st Thou spy," are given in Thring's Collection, 1882.
--John Julian, Dictionary of Hymnology (1907)