I have desired, and I have been desired;
But now the days are over of desire,
Now dust and dying embers mock my fire;
Where is the hire for which my life was hired?
Oh vanity of vanities, desire!
Longing and love, pangs of a perished pleasure,
Longing and love, a disenkindled fire,
And memory a bottomless gulf of mire,
This line is a reference to the first line of the Book of Ecclesiastes in the Old Testament. This allusion to  Ecclesiastes 1:2  has shown how the speaker is battling against the pull of earthly desires to achieve a more spiritual life. 
 Vanity of vanities, saith the Preacher, vanity of vanities; all is vanity. 
 It is repeated in every stanza, a device known as  anaphora .
Soeur Louise De La Misericorde