Quakers traditionally hold to core Protestant Christian beliefs, including the divinity of Jesus Christ, the Trinity, and salvation. Yet, like other Christian denominations, they hold unique beliefs as well.
"Inner Light" is a term Quakers use to describe the theological belief that the presence of God resides inside every person. John 1:9 is a verse central to this doctrine:
"That was the true Light, which lighteth every man that cometh into the world." KJV
"The true light that gives light to every man was coming into the world." NIV
This doctrine was important as Quaker founder, George Fox, argued that Christians didn't need the Church to know God; they could just look inward. Quaker apologist, Robert Barclay, writes:
"This most certain doctrine being then received, that there is an evangelical and saving Light and grace in all, the universality of the love and mercy of God towards mankind, both in the death of his beloved Son the Lord Jesus Christ, and in the manifestation of the Light in the heart, is established and confirmed, against all the objections of such as deny it."
Quakers are encouraged to be attentive to their inner light and then share with others what they believe God revealed to them, particularly in the setting of corporate worship.
Most Quakers don't practice the outward sacraments of water baptism and communion like many other Christian denominations do. Refusal to participate in outward sacraments is intended to safeguard Quakers from reducing an observance to a purely external act, void of the presence of God. However, some Quakers suggest that Christians experience an inward "baptism" of the Holy Spirit and eating meals with others is a type of "communion."
The "Peace Testimony" of Quakers isn't a theological doctrine, but an application of Jesus' teaching to love one's enemies by refusing to engage in physical combat. The Quaker peace testimony takes on different forms, from claiming the status of conscientious objector during times of war to refusing to pay taxes that are used for military purposes. The Quaker community won the Nobel Peace Prize in 1947.
Quakers regularly meet together to worship, a time characterized by periods of silence and the lack of a human leader such as a minister or pastor. Traditionally, when Quakers worship together they will wait upon the Holy Spirit to speak through their inner light. Many people may speak at a worship service and their words may include testimonies and words of encouragement.