Here is an excerpt from one of the posts in that thread:
Quakerism is a path that is traditionally a mystical approach to Christianity. It is about one's personal relationship and connection to God, and God is typically seen as both immanent (within each person, and the earth in general) and transcendent. Revelation (messages given to us by God) is understood to be personal and on-going, and thus Quakers are not limited by the Bible in gaining wisdom from God, though they generally uphold the Bible as sacred text. Below is a general summary of the core beliefs of liberal Quakers, but the nature of the denomination is such that individual beliefs vary greatly and are tolerated. This summary is based on "Facts about Friends" by Ted Hoare, paraphrased by myself and with small additions of my own beliefs as example.
1. Belief in the individual direct relationship with God.
Quakers do not think ministers or priests are necessary for intercession between individuals and God. Only Jesus Christ can speak to each of us, and we are each responsible for our own spiritual development. We are each of us ministers, both to ourselves and to our fellow humanity. We are each responsible for studying the Bible and interpreting it, for putting together a worship and study program in our lives, and for communicating our experience of God to others.
2. The Bible is not the final revelation of God.
The Bible was written by people who were inspired by the Holy Spirit, and we as believers must be inspired by that same Spirit when we read the Bible, which speaks the wisdom from the text to our hearts. The text of the Bible is seen as something which, when read in the appropriate time and Spirit, gives us wisdom and furthers our spiritual development. Liberal Quakers typically do not believe the Bible is infallible or inerrant in a literal sense, but rather that it is so in a Spirit-guided sense. That is, all the text of the Bible speaks to people's Spirit-inspired writings- attempted expression of their experience of God and the wisdom they gained from these experiences. Thus, the Bible, if read with the guidance of the Spirit, will lead the believer to an ever-greater awareness of God and will provide wisdom that speaks to the believer's life. The question a liberal Quaker asks in Bible study and prayer is not... did this happen? But rather, what does this mean for me? For example, when I read the creation account of Genesis, my concern is not- six-day creation or several billion years? It is, what does the story of Genesis mean for me? What wisdom does it give me into the nature of God, of humanity, of our purpose on earth and the obstacles we must face?
3. The divine light
Quakers believe in a concept generally known as the divine light. Like Celtic Christians, Quakers generally believe that people are essentially good. We are created in the image and likeness of God (in a spiritual sense), we are the children of God, and as such, we were given a measure of God as the essential core of our being. This divine light is the immanence of God residing within us, and every human on earth has it. In accordance to what we do with it, more may be given to us. Thus, if we hide our light under a bed, as Jesus taught, the light will be clouded by the darkness around it and we may even forget that it is there. This is what happens to us when we allow sin and wrong-doing to dominate our lives. The darkness cannot overcome the light, and so our essential core is still of God, but we have forgotten about it and thus we are dead to its existence. Conversely, if we recognize the divine light and seek to fan it into radiant flame, putting it where all the world can see it and making it useful, we will be given ever more light by God. This divine light both leads us on our inward journey home to unity with God, and also provides a beacon of light in a world often dark, lighting the path for others. Quakers believe Jesus possessed this divine light without measure, so he was the Light and the Light within is Jesus Christ.
4. The inner voice
Quakers believe that if one faithfully waits in silence before God, there will be moments when God speaks to their hearts directly. This is a mystical practice- we seek direct communication with God and we believe God really does speak to us. This is why Quaker (Friends) meetings are silent- it is through silence that we can still our minds and patiently wait for the Spirit to lead us. Thus, Quakers have an ongoing revelation from God. This practice need not be during a meeting, but can also come during times of solitude. Meetings and discussion with other Christians can be helpful, however, in one's dutiful contemplation of the messages one receives. It is important to distinguish between messages that come from God, from one's deeper self, and from other powers (as a Druid, these powers include ancestor, place, nature, etc. spirits, and as a Christian there are certainly spirits that are not in accordance with God- we must be careful not to cultivate beliefs in these- my guess is the Quakers vary in terms of what powers they think are out there). The Bible also provides a guide to discerning contemporary revelation; Jesus taught that good entities will bear good action (a good tree will bear good fruit), and that these fruits are the gifts of the Spirit. God-given wisdom does not encourage immoral or harmful action, nor does it point toward worshipping any other than God, in my own experience.
5. Gender (and other) equality
All children of God are held as equals. Thus, race, gender, etc. do not matter before God and thus should not in this world. Human honors and distinctions are meaningless to God, and so all are equal in His eyes- He only sees our souls and the journey we have taken through life. This is why the historical Quakers (and many contemporary folks) choose a simple life, a general lack of materialism, plain dress, and plain speech.
6. Inward and outward journeys
Quakers are not just about beliefs. They are fundamentally about experiencing God for oneself. God is seen as immanent in everything- all life is sacred. There is no sacred time, building, or action. Everything ought to be consecrated to God, and all one's actions should be worshipping God. I think this is similar to the idea of mindfulness in Buddhism. Thus, it is crucial to journey both inwardly and outwardly. The inward journey is the spiritual journey you make in your heart and soul- the time you spend silent with God, your prayer work, your mystical experiences. The outward journey is the spiritual journey you make in your actions in the world- being Christ's hands and feet, as it were- taking the wisdom you gain and putting it into practical action. If one only takes the inward journey, one becomes selfish, and isn't following Christ's example of "doing unto the least of these." If one only takes the outward journey, one gets burned out, because there is no time of restoration, support, or refreshment. Essentially, the inward/outward journey parallels Christ's command to "love God and love neighbor as oneself." This combination is why Quakers have always been very devoted activists- their outward journeys have contributed to reforms of institutions, the end of slavery, improving labor conditions, and other political, social, and environmental action.
Quakers are generally pacifists, and are actively so. Aside from various teachings of Jesus on peace-making and forgiveness, and Christ's own example of self-sacrifice unto death over using power for oneself, the principle of peace is also an outgrowth of the belief in the divine light. Since all human beings contain within them the light of God, even if clouded or hidden, it is denying the Spirit within them to kill another. Stemming from this, Quakers have a great love for democracy in a very idealistic sense. Quakers do not believe any person should overcome another- by physical force or otherwise. Thus, the emphasis for Quakers is always respectful discussion reaching some conclusion, rather than a win/lose contest. Cooperation, not competition, is the overarching attitude. Because the divine light is within each of us, each of us could be right or wrong, and we must be open to the Spirit speaking through others as well as ourselves. Thus, the divine light is the source of unity, both between humanity and God and between people.
8. Doctrine and diversity
Quakers don't have a creed, or a doctrine. People are Quakers because they independently come to a few conclusions, generally those listed here, not because they have a uniting doctrine. Aside from silent times, there is little that unites Quakers in practice and Quaker meetings and churches vary a lot. Aside from a few commonly held ideas, there is great diversity in beliefs. Many Quakers also recognize and study the wisdom given from God to other religious traditions. So beliefs about things like the afterlife, judgement, end times (and interpretation of Revelations), evolution/creation/origins, heaven/hell, etc. are very diverse and Quakers don't have a problem with that diversity, because each person is perceived to be receiving the wisdom s/he needs at that given time. Many liberal Quakers do not believe heaven and hell are literal places, nor do many believe in literal interpretations of accounts like the creation story of Genesis or the prophecies of the end times. Many liberal Quakers believe that the grace of God is extended to all people, and everyone will enter the kingdom of heaven, which some (myself included) believe is being with God. Some Quakers believe this occurs through reincarnation until one comes to truly know God, and others believe everyone reaches this point at death no matter what their life spoke to. What this unity with God means is also diverse, but is generally perceived to be spiritual (the resurrection body seen as a spirit-body) and not physical, as God is believed by many to have no form. Beliefs about Jesus vary as well- some believe him to be God incarnate, others a human who so embraced the divine light he became utterly unified with God, still others a unique aspect of God incarnate (for myself, the aspect of the unity of divinity and creation). But all hold Jesus to be central to their faith, and his teachings to form the essential guide and example for our lives.
9. Other religions
Quakers believe the divine light is in everyone, in every religion and culture. The Light of Christ knows no boundaries, and my own belief is that it also knows no time. Christ was with us in our origins, and Christ is with us always. It is only our limited perception of linear time that puts Christ on a certain point in a one-direction timeline of existence. Quakers believe that many people who never knew the historical Christ knew or know the Eternal Christ, the Word, the logos of the Gospel of John. We believe that wisdom and insight can be gained through the study of other religions and discussion with their followers. The Spirit may speak to the divine light within a Muslim, or a Hindu, or an earth-centered person. In our own spirituality, the centrality of Jesus and his teachings are the foundation and are of the upmost importance. While we are generally tolerant and even enthusiastic in our dialogue with other religions, we do not stray from the centrality of Jesus (otherwise, of course, we would not be Christian!).
The summary, directly quoted, as it is beautiful:
"The Religious Society of Friends is an alternative Christianity which emphasizes the personal experience of God in one's life. Quakers understand the necessity of first listening to God before working in the world. They affirm the equality of all people before God regardless of race, station in life, or sex and this belief leads them into a range of social concerns. Being "Children of the Light" they find recourse to violence intolerable. Quaker thought is both mystical (waiting upon God) and prophetic (speaking truth to power). Friends believe that God's revelation is still continuing, that God is not absent or unknowable but that we can find God ourselves and establish a living relationship thus being able to live in the world free from the burden and guilt of sin. It is the search for a closer relationship with God who is the Way. Religious knowlede, like the appreciation of beauty, is not attained by a logical process of thought but by experience and feeling. Quakers maintain that the teaching of Jesus is a practical metod for the guidance of the world today, that religion is concerned with the whole of life, and that, beyond a certain point, definition becomes a limitation."
Edited to add- one link I have found helpful: http://www.quaker.org/
This is the link to the Religious Society of Friends and has links to Friends' literary works, organizations and meetings, social and environmental work, etc.
Peace to you in your search,