Though holy doctors have uncovered many mysteries and wonders, and devout souls have understood them in this earthly condition of ours, yet the greater part still remains to be unfolded by them, and even to be understood by them.
We must then dig deeply in Christ. He is like a rich mine with many pockets containing treasures: however deep we dig, we will never find their end or their limit. Indeed, in every pocket new seams of fresh riches are discovered on all sides.
For this reason the apostle Paul said of Christ, "In him are hidden all the treasures of the wisdom and knowledge of God." The soul cannot enter into these treasures, nor attain them, unless it first crosses into and enters the thicket of suffering, enduring interior and exterior labors, and unless it first receives from God very many blessings in the intellect and in the senses, and has undergone long spiritual training.
The gate that gives entry into these riches of his wisdom is the cross; because it is a narrow gate, while many seek the joys that can be gained through it, it is given to few to desire to pass through it.
-- Saint John of the Cross from a spiritual canticle by him
