In what way did the Quakers participate in the early fight for human rights?

Quakers participated in the early fight for human rights because the Quaker religion finds value in all of humanity. Quakerism supports the dignity of people and states that all humans have an "inner light" which comes from God. Therefore, Quakers historically have been very involved in human rights and social justice work more generally because of their faiths grounding in humanism and the value in all of humanity.