One way in which Quakers, also called Friends, challenged existing norms is by rejecting the Protestant belief referred to as sola scriptura, which is the belief that, since the Bible is God's written word, it is "self-authenticating, clear, and its own interpreter" (New World Encyclopedia, "Quakers"). Quakers instead believe that Christ is the Word of God and, therefore, place more emphasis on listening to the Holy Spirit, a gift of Christ, for guidance rather than looking to the Bible for guidance.
However, this belief has created schisms within the Quaker sect. Early Quakers believed that the Holy Spirit would never guide them to do anything that contradicted the Bible, which led some Quakers to think that, in times of conflict, the Bible should be considered the authoritative source. Modern-day Evangelic Quakers have even come to believe the Bible is absolutely authoritative. Still, other Quakers continue to disagree and even feel the Holy Spirit can lead individuals in ways that contradict the Bible and are spiritually acceptable. Some even go so far as to completely reject the Bible.
A second way in which Quakers challenge existing norms is by rejecting the creeds set forth by other Christian denominations. A creed is a statement of beliefs shared by members of the same religion. The Nicene Creed is used by the Eastern Orthodox, Roman Catholic, Anglican, and Protestant churches. It was adopted by the First Council of Nicaea in AD 325 and modified at the First Council of Constantinople in AD 381; it proclaims the belief in one God and one Lord Jesus Christ who was incarnate, suffered, and rose again. Quakers reject the formulation of creeds because they believe that every individual receives his/her own revelations through the Holy Spirit.
Beyond spiritual beliefs, Quakers also challenged social norms by being anti-war activists due to their belief in pacifism; by being women's rights activists due to their belief that all are equal before God, men and women alike; and by denouncing materialism.