Nisibene Hymns 27, stanza 8 — as quoted by Pitre (p 38)
Only you [Jesus] and your Mother are more beautiful than everything. For on you, O Lord, there is no mark; neither is there any stain in your Mother.
No freely usable English translation of this passage is online, so the note keeps Pitre's quotation and links to the full text.
In Jewish Roots of Mary
Why it is cited
'On you, O Lord, there is no mark; neither is there any stain in your Mother.' Ephrem's fourth-century statement of Mary's sinlessness, which Pitre pairs with Augustine.
Notes
Not available in a public-domain English translation. NPNF2-13 (Gwynn) translates Nisibene Hymns I–XXI, XXXV–XLII and LII–LXVIII only; its placeholder for the gap reads '[XXII.–XXV. (wanting); XXVI. (only a fragment remains); XXVII.–XXXIV. (relate to Edessa and Carrhæ).]' — hymn 27 is omitted, and New Advent (3702a–f) reproduces the same selection. The stanza ('You alone and your Mother are more beautiful than any others ... no blemish in you nor any stains upon your Mother') is quoted in modern works, e.g. L. Gambero, Mary and the Fathers of the Church (Ignatius Press, 1999); the critical edition is Beck, CSCO 218/219 (Syriac/German). Quote briefly with attribution.