Wikipedia
Light of God, Light of Christ, Christ within, That of God, Spirit of God within us, Light within, inward light and inner light are related phrases commonly used within the Religious Society of Friends (Quakers) as metaphors for Christ's light shining on or in them. 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)." 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.
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". As such, the word light is commonly used by Christians (including Quakers) as a metaphor for Christ, derived from many Biblical passages including John 8:12, which states: Quakers take this idea of walking in the Light of Christ to refer to God's presence within a person, and to a direct and personal experience of God, although this varies to some extent between Quakers in different yearly meetings. Quakers believe not only that individuals can be guided by this light, but that Friends might meet together and receive collective guidance from God by sharing the concerns and leadings that he gives to individuals. This is often done in meeting for worship; Pierre Lacout, a Swiss Quaker, describes a "silence which is active" causing the Inner Light to "glow", in his book God is silence. In a Friends meeting it is usually called "ministry" when a person shares aloud what the Inner Light is saying to him or her. The term inward light was first used by early Friends to refer to Christ's light shining on them; the term inner light has also been used to since twentieth century to describe this Quaker doctrine. Rufus Jones, in 1904, wrote that: "The Inner Light is the doctrine that there is something Divine, ‘Something of God’ in the human soul". Jones argued that his interpretation of the Quaker doctrine of the inner light was something shared by George Fox and other early Quakers, but some Quaker theologians and historians, most notably Lewis Benson reject this viewpoint.
Usage examples of "inward light".
But it is good to break this order if one feels oneself very distinctly impelled to it by the inward light of Christ, by true knowledge, by the firm consciousness of truth, and moreover knows, knows with absolute certainty, that one has the power and the abilities for enduring and struggling, for resisting the inevitable enmity of the world, for surviving her hatred and persecution, for proving indeed one's good right to secede and to be original.
There were these lights then: darkening sky, fireflies, phosphorescent blossoms that seemed to shine not by reflection but by some mild inward light of their own.
But these kinds of inspiration Lydgate regarded as rather vulgar and vinous compared with the imagination that reveals subtle actions inaccessible by any sort of lens, but tracked in that outer darkness through long pathways of necessary sequence by the inward light which is the last refinement of Energy, capable of bathing even the ethereal atoms in its ideally illuminated space.