John of the Cross, Ascent of Mount Carmel

THESE lines take as a metaphor the miserable estate of captivity, a man's deliverance from which, when none of the gaolers' hinder his release, he considers a 'happy chance.' For the soul, on account of original sin, is truly as it were a captive in this mortal body, subject to the passions and desires of nature, from and subjection to which it considers its having gone forth without being observed as a 'happy chance' -- having gone forth, that is, without being impeded or engulfed by any of them.

2. For to this end the soul profited by going forth upon a 'dark night' -- that is, in the privation of all pleasures and mortification of all desires, after the manner whereof we have spoken. And by its 'house being now at rest' is meant the sensual part, which is the house of all the desires, and is now at rest because they have all been overcome and lulled to sleep. For until the desires are lulled to sleep through the mortification of the sensual nature, and until at last the sensual nature itself is at rest from them, so that they make not war upon the spirit, the soul goes not forth to true liberty and to the fruition of union with its Beloved.

END OF THE FIRST BOOK