George Fox, the founder of Quakerism, spent years in spiritual ferment, talking with ministers, or priests and professors, as he often calls them. None seemed able to address his concerns. As Fox reached the bottom of his despair over his concerns and the inability of the ministry to address them, he was raised by the insight that created Quakerism:
And when all my hopes in them and in all men were gone, so that I had nothing outwardly to help me, nor could tell what to do, then, Oh then, I heard a voice which said, "There is one, even Christ Jesus, that can speak to thy condition," and when I heard it my heart did leap for joy. Then the Lord did let me see why there was none upon the earth that could speak to my condition, namely, that I might give him all the glory; for all are concluded under sin, and shut up in unbelief as I had been, that Jesus Christ might have pre-emninence, who enlightens, and gives grace, faith, and power. Thus, when God doth work who shall let [prevent] it? And this I knew experimentally.
This founding story combines key elements that appear elsewhere in Fox's Journal, and which develop through Quakerism:
Christ (through the Inner Light) "enlightens, and gives grace, faith, and power."
Even the best of men - priests and ministers included - can't communicate this grace.
Fox knows this through his experience of God - "experimentally" meaning "through experience" - not through the ministry or even the scriptures. (It corresponds well to scriptures, but it is Christ's authority which makes it true, not the Bible's.)
This initial insight may in some ways been seen as completing the Reformation, as James Wood pointed out in his The Distinguishing Doctrines of the Religious Society of Friends:
The true understanding of this requires some definite test as to what is the fundamental difference between Catholicism and Protestantism. The formula of Schleiermacher is generally accepted by both sides as a correct statement of this. "Catholicism makes the believer's relation to Christ depend upon his relation to the church; Protestantism make the believer's relation to the church depend on his relation to Christ." It follows from this that if the believer's relation to Christ is made, in any degree, dependent upon his observance of any ordinance or ceremony of the church, or upon any exercise of sacerdotal authority by its priests or ministers, in so far, the fundamental principle of Protestantism is violated and the principle of Catholicism is maintained.
...both in the Church of England and among the numerous bodies of dissenters that arose, some upon one point of doctrine or practice and some on another, there was continually some recognition of the Catholic principle, and it was not until a hundred years had passed after the Reformation began that a body arose that clearly and unequivocally took the position that the believer's relation to Christ does not depend upon his relation to the church, and which brought the Reformation to its logical conclusion. That body was the Society of Friends.
Much to contemplate.