There is one quirk of Quakerism that outsiders may not be familiar with.
Friends place personal revelation above scripture.
The Bible is important, but when it comes right down to it. We consider it to be just one way to commune with the Light.
Quaker reliance on personal revelation dates back to our founder George Fox. Fox preached that within every person there is a measure of the Holy Spirit. In it's modern form we refer to this as, "That of God in Everyone," or "The Light Within."
Quaker Silent Worship has as it's express purpose reaching towards that light. It is an attempt to commune with the Spirit and receive God's wisdom.
This wisdom is then meant to inform our actions and guide us in a careful and caring life.
We follow personal revelation because of a simple fact. Over the last Two-Thousand years morality has advanced. It continues to do so. In the past the Divine was only able to reveal what the people alive at the time were ready to hear.
I tend to see the history of the Judeo-Christian tradition as a maturation process. You have the early Hebrews. Who were violent, arrogant, and obsessed with purity and cleanliness. Like a young child (who very often can be described by my previous sentence) they needed a lot of rules. Just as you need rules telling a small child not to hit their sister, or pull a vase down on themselves. The Ancient Hebrews needed rules telling them not to eat un-refrigerated and non-preserved pork and shellfish in the desert.
Then you have the loosening of the rules with Yeshua of Nazareth. Just as with a teenager, you are able to rely on your children to make their own judgements. Yeshu made it clear that the intent behind the rules was more important than the letter of the rules. That God is love, and following God will always produce love in this world.
Now, for the most part society has advanced to adulthood. Morality overall has advanced to the point where the Divine does not need to intercede directly on a constant basis.
Just as adults only need their parents when they ask for help. We only need Divine Assistance when we ask for it. Although, like any good parent, sometimes he will help us with something more difficult without actually letting us know.
Of course there are those who ignore current Morality and the guidance of the Divine. Who, for whatever reason act in selfish and short sighted ways. Who instead of loving their neighbors, find reasons to hate and exclude. Who like the proverbial Tax Collector, only love those who love them.
Following the Light we receive guidance to care for everyone. For all people contain That of God within. Even when it is so hard to see.