From a letter entitled, "Spiritual Blindness"
..."Regeneration, or that great change without which a man cannot see the kingdom of God, is the effect of the Almighty power. Neither education, endeavors, nor arguments can open the eyes of the blind. It is God alone, who at first caused light to shine out of darkness, who can shine into our hearts, " to give us the light of the knowledge of the glory of God in the face of Jesus Christ." People may attain some natural ideas of spiritual truths by reading books, or hearing sermons, and may thereby become wise in their own conceits; they may learn to imitate the language of an experienced Christian; but they know not what they say, nor whereof they affirm, and are as distant from the true meaning of the terms, as a blind man, who pronounces the wordsblue or red, is from the ideas which those words raise in the mind of the person who can distinguish colors by his sight. And from hence, we may infer the sovereignty, as well as the efficacy, of grace; since it is evident, not only that the objective light, the word of God, is not afforded universally to all men; but that those who enjoy the same outward means, have not all the same perceptions. There are many who stumble in the noon day, not for want of light, but for the want of eyes; and they who now see were once blind, even as others, and had neither power nor will to enlighten their own minds. It is a mercy, however, when people are so far sensible of their own blindness, as to be willing to wait for the manifestation of the Lord's power, in the ordinances of His appointment. He came into the world, and sends forth His Gospel, that those who see not, may see; and when there is a desire in the heart for spiritual sight, it shall in due time be answered."