The concept of the Inner Light is a central belief of the Quaker faith. Synonyms for Inner Light include "Light of God," "Light of Christ," "Spirit of God within us," "Light within" and "Christ within." Some people identify it with the expression "that of God in everyone," which was first used by one of the founders of the Society of Friends, George Fox. The related term Inward light appears in older Quaker writings but is not used as often now. This term evokes an image of people being illuminated by the light of God or Christ, rather than having a light of their own inside them.
The purpose of the Inner Light
Quakers believe that one can only come to know God through experience (that which is inwardly revealed). George Fox continually turned troubled questioners to 'the teacher within'. The purpose of the Inner Light is to provide for this inward experience by discerning between good and evil and opening one to God's guidance in determining which path should be taken.
Because all people are indwelt with this Inner Light Quakers believe that where there is goodness there is God. The Light therefore forms a consciousness of the unity of all human beings.
The Inner Light vs. impulse and conscience
It is important to understand that the Inner Light is distinct from impulses which originate with oneself. It is indeed a central task in the life of a Quaker to distinguish between the two. In fact, as Marianne McMullen pointed out, a person can be prompted to say something in meeting that is contrary to what he or she thinks. 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.
The Inner Light and the Bible
While there is no agreement amongst Quakers as to the relation of the Inner Light to the Bible, most Quakers, especially in the past have looked to the Bible as a source of wisdom and guidance which is inspired by God. Quakers have generally tended to regard present, personal direction from God more authoritative than the text of the Bible. Early Quakers, like George Fox and Robert Barclay, did not believe that promptings which were truly from the Spirit within would contradict the Bible. They did, however, believe that to correctly understand the Bible, one needed the Inner Light to clarify it and guide one in applying its teachings to current situations. In the nineteenth century some Friends believed that other Friends were using the concept of the Inner Light to justify views that were unbiblical. These Orthodox Friends believed that the Bible was more authoritative than the Inner Light and should be used as a test of personal leadings. Friends are still formally, but usually respectfully, divided on the matter.