Spiritual Guide Which Disentangles the Soul - Michael de Molinos - 1st Book - Chapter 6

There are two sorts of darkness.

Unhappy. Arises from sin.
Happy. In the soul to ground it and settle it in virtue. These enlighten and fortify the soul.

The happy darkness is where God can infuse the supernatural light. Wisdom and strong love are begotten, the soul is annihilated. By darkness God purges the senses and sensibility, which hinder the mystical progress.

So embrace this happy darkness (again, dryness of prayer). Drop the desire to know or understand anything, to search after those sensible devotions and desire to do only what is the will of God and the pleasure of God.