It was propagated by the founder of the Quaker movement, George Fox, who "preached faith in and reliance on 'inward light' (the presence of Christ in the heart)".
[1][2] The first Quakers were known to sit in silence and meditate on the words of the Bible until they felt the inward light of God shining upon them and the Holy Spirit speaking.
[3] The concept was highly important to early Quakers, who taught: "God reveals Himself within each individual's conscience and consciousness by the Holy Spirit, Christ Himself being the Light to illuminate man's sinfulness and lead in the way of truth and righteousness.
"[4][5] The Key to the Faith and Practice of the Religious Society of Friends states that the Inward Light is "both the historical, living Jesus, and as the Grace of God extended to people that simultaneously makes us conscious of our sins, forgives them, and gives us the strength and the will to overcome them" and "teaches us the difference between right and wrong, truth and falseness, good and evil".
[10] In a Friends meeting it is usually called "ministry" when a person shares aloud what the Inward Light is saying to him or her, which is revealed "by the direct prompting of Christ through his Holy Spirit.
They show that the work of the law is written on their hearts, while their conscience also bears witness, and their conflicting thoughts accuse or excuse them on the day when, according to my gospel, God judges the secrets of men by Christ Jesus (Romans 2:14–16).
The Cross is no "dead fact stranded on the shore of the oblivious years", but is to be a living experience deep in the heart of the believer, and changing his whole life.
All real experience of the Cross must lead, he thought, to the same way of life that brought the Master there—to the way of humility and non-resistance, of overcoming evil by the sole force of love and goodness.
"[19] Many Friends consider this divine guidance (or "promptings" or "leadings of the Spirit") distinct both from impulses originating within oneself and from generally agreed-on moral guidelines.
[20] In other words, Friends do not usually consider the Inner Light the conscience or moral sensibility but something higher and deeper that informs and sometimes corrects these aspects of human nature.
They did, furthermore, believe that to correctly understand the Bible, one needed the Inward Light to clarify it and guide one in applying its teachings to current situations.
[5] These Orthodox Friends held that the revelations of the Inward Light would not be in contradiction to the teachings of the Bible: "the Scriptures were foundational to Christian doctrine, and the indwelling Spirit was the immediate guide for holy living and worship.