G. R. S. Mead 
The Hymn of the Robe of Glory, The Hymns of Hermes [EPUB ebook] 

8They girt me with Adamant [also]That hath power to cut even iron.9My Glorious Robe they took off me Which in their love they had wrought me, 10And my Purple Mantle [also]Which was woven to match with my stature.11And with me They [then] made a compact;In my heart wrote it, not to forget it:12’If thou goest down into Egypt, And thence thou bring’st the one Pearl–13′[The Pearl] that lies in the Sea, Hard by the loud-breathing Serpent, –14′[Then] shalt Thou put on thy Robe And thy Mantle that goeth upon it, 15’And with thy Brother, Our Second, Shalt thou be Heir in our Kingdom.’