What is The Wall, the Dark Night of the Soul?

I shared these two articles last week, but I wanted to make sure everyone had a chance to look at them. They pertain to the discussion on The Wall/The Dark Night of the Soul...

What is a Dark Night of the Soul? and The Dark Night of the Soul by R.C. Sproul. 

The first deals with the history of the the "Dark Night of the Soul" concept: 

The phrase “dark night of the soul” comes from a poem by St. John of the Cross (1542-1591), a Spanish Carmelite monk and mystic...  The monk taught that one seeking God will cast off all attachments to this world and live a life of austerity. Before attaining union with God, however, the soul must pass through a personal experience of Christ’s passion. This time of testing and agony is accompanied by confusion, fear, and uncertainty—including doubts of God—but on the other side are Christ’s glory, serenity, and a mystical union with God.

The second deals with the concept of the Dark Night as it might be understood in the wider Christian community: 

This phenomenon describes a malady that the greatest of Christians have suffered from time to time. It was the malady that provoked David to soak his pillow with tears. It was the malady that earned for Jeremiah the sobriquet, “The Weeping Prophet.” It was the malady that so afflicted Martin Luther that his melancholy threatened to destroy him. This is no ordinary fit of depression, but it is a depression that is linked to a crisis of faith, a crisis that comes when one senses the absence of God or gives rise to a feeling of abandonment by Him.