John of the Cross' Dark Night of the Soul

The Dark Night of the Soul is a second commentary on the same poem from Ascent of Mount Carmel. Here is the translation we read. It is about the passive nights of the soul, whereas Ascent is about the active nights.

One dark night,
fired with love's urgent longing
--ah, the sheer grace!--
I went out unseen,
my house being now all stilled.

The dark night in the first stanza is "purgative contemplation", which passively causes the the soul to leave love of self and things for union with God.

John begins by describing the imperfections of beginners in the spiritual life, in the areas of pride, spiritual avarice, lust, spiritual anger, spiritual gluttony, spiritual envy and sloth.
Pride is seeking to be esteemed by others for your achievements; seeking gratification in how others think of you. Humility is the virtue that regulates self-esteem: regulate according to God's esteem for you. When we regulate self-esteem independently of this, we esteem ourselves wrongly. The way you see yourself sets up how you act: if you don't see yourself as a son of God, you'll act beneath your dignity. Try to laugh at your vanity: the Enemy hates humour, so laugh about it when you are humiliated. When someone purposefully, cruelly humiliates you, then you are especially Christlike. Pride can follow all of us into the confessional, where we might not clearly relate our sins. But it is so much more important to get your sin forgiven than what the old man thinks of you. St John describes some persons who are "anxious that God removes their faults and imperfections, but their motive is personal peace rather than God." We should desire peace, without being anxious. To counter what John describes, thank God for your faults, because they keep you humble. Do not be so foolish as to think that holiness is within your grasp; the only way to get it is to receive it from God. Another way to regulate pride is to learn to be in God's presence without consolation. Let God be the master of your prayer time. To heal your big fat ego, waste time with God. Keep going to daily holy hours even if they are un-consoling and boring. A big lesson in humility for seminarians is to lovingly and eagerly accept formation: "Yet these humble souls, far from desiring to be anyone's teacher, are ready to take a road different from the one they are following, if told to do so."
Spiritual avarice is when a person sees spirituality as the acquisition of teachings, religious articles, or a preoccupation with the externals of liturgy. This can cause the person to seek satisfaction in liturgy which appeals to his personal preferences, rather than in praising God. The antidote for this is spiritual poverty, produced by the Holy Spirit in contemplation.
Lust will get worse before it gets better. It can lead us to union with God, as can pride, if we have tears of compunction for our sinful instincts. When you have an instinct to lust, just pray "Lord, have mercy."
Anger is discussed as anger at yourself over not becoming holy quickly enough; St John says, "they do not have the patience to wait until God gives them what they need". The cure is spiritual meekness, learning to be patient with God.
Spiritual gluttony is a craving for consolation in prayer. St John says that when these persons receive Communion, they are more concerned with getting "feeling and satisfaction rather than humbly praising and reverencing God dwelling within them." Our first prayer after receiving Christ should always be praise and worship of the Trinity and particularly Christ.
Spiritual sloth is a reluctance or refusal to pray, when it is not consoling.
A good rule of thumb with regards to these imperfections: if there is a passage you can't relate to or identify with, it's a safe bet that that is such a huge problem for you that you don't even see it, it's so permeated into you.

St John says that God delivers beginners of these imperfections through the dark night, through "pure dryness and interior darkness".

The dryness of the dark night is given to the soul so that you will become free to rest in God alone; he won't let anything else console you while you're in the dark night. In the dark night God is not communicated by senses or thought, but by "simple contemplation", "in which there is not discursive succession of thought." The soul has to abandon itself to this process, accepting that it can't do anything, and in prayer just waste time with God.

Entering the dark night, the soul is "attracted by the love of God and enkindled in it". Pss 73 and 43 describe this longing.

In the dark night, prayer feels like a waste of time and scripture passages won't seem meaningful. At these times make an act of faith that God is present, and attend to God; stop distracting yourself with reading, emotions, or imagination.

St John of the Cross says that the benefits of the dark night are: self-knowledge, about our lowliness; knowledge of God, of his grandeur and majesty; humility; and love of neighbour.