Thanks so much, Daniel! Beautiful words, and very evocative of Ennis's journey. Here are two excerpts I found from Wikipedia that give some background:
The term and metaphysicality of the phrase "dark night of the soul" are taken from the writings of the Spanish poet and Roman Catholic mystic Saint John of the Cross, a Carmelite priest in the 16th century. Dark Night of the Soul is the name of both a poem, and a commentary on that poem, and are among the Carmelite priest's most famous writings. They tell of his mystic development and the stages he went through on his quest for holiness.
The "dark night" could generally be described as a letting go of our ego's hold on the psyche, making room for change that can bring about a complete transformation of a person's way of defining his/her self and their relationship to God. The interim period can be frightening, hence the perceived "darkness". In the Christian tradition, during the "dark night" one who has developed a strong prayer life and consistent devotion to God suddenly finds traditional prayer extremely difficult and unrewarding for an extended period of time. The individual may feel as though God has suddenly abandoned them, or that their prayer life has collapsed.
Rather than being a negative event, the dark night is believed by mystics and others to be a blessing in disguise where the individual is trained to grow from vocal and mental prayer, to a deeper contemplative prayer of the soul. Particularly in Christianity, it is seen as a severe test of one's faith. The Dark Night comes in two phases: a first "Night of the Senses," and a second "Night of the Spirit."
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Dark Night of the Soul (from which the spiritual term Dark Night of the Soul takes its name) narrates the journey of the soul from her bodily home to her union with God. It happens during the night, which represents the hardships and difficulties she meets in detachment from the world and reaching the light of the union with the Creator. There are several steps in this night, which are related in successive stanzas.