The Religious Society of Friends, also known as Quakers, petitions U.S. Congress for the abolition of slavery.

In the United States, abolitionism, the movement that sought to end slavery in the country, was active from the late colonial era until the American Civil War, the end of which brought about the abolition of American slavery through the Thirteenth Amendment to the United States Constitution (ratified 1865).

The anti-slavery movement originated during the Age of Enlightenment, focused on ending the trans-Atlantic slave trade. In Colonial America, a few German Quakers issued the 1688 Germantown Quaker Petition Against Slavery, which marks the beginning of the American abolitionist movement. Before the Revolutionary War, evangelical colonists were the primary advocates for the opposition to slavery and the slave trade, doing so on humanitarian grounds. James Oglethorpe, the founder of the colony of Georgia, originally tried to prohibit slavery upon its founding, a decision that was eventually reversed.

During the Revolutionary era, all states abolished the international slave trade, but South Carolina reversed its decision. Between the Revolutionary War and 1804, laws, constitutions, or court decisions in each of the Northern states provided for the gradual or immediate abolition of slavery. No Southern state adopted similar policies. In 1807, acting as soon as the Constitution allowed, Congress made the importation of slaves a crime. Immediate emancipation became a war goal for the Union in 1862 and was fully achieved in 1865.

Quakers are people who belong to a historically Protestant Christian set of denominations known formally as the Religious Society of Friends. Members of these movements are generally united by a belief in each human's ability to experience the light within or see "that of God in every one". Some profess a priesthood of all believers inspired by the First Epistle of Peter. They include those with evangelical, holiness, liberal, and traditional Quaker understandings of Christianity. There are also Nontheist Quakers, whose spiritual practice does not rely on the existence of God. To differing extents, the Friends avoid creeds and hierarchical structures. In 2007, there were about 359,000 adult Quakers worldwide. In 2017, there were 377,557 adult Quakers, 49% of them in Africa.Some 89% of Quakers worldwide belong to "evangelical" and "programmed" branches, that hold services with singing and a prepared Bible message coordinated by a pastor. Some 11% practice waiting worship, or unprogrammed worship (commonly Meeting for Worship), where the unplanned order of service is mainly silent and may include unprepared vocal ministry from those present. Some meetings of both types have Recorded Ministers present; Friends recognised for their gift of vocal ministry.The proto-evangelical Christian movement known as Quakerism arose in mid-17th-century England from the Legatine-Arians and other dissenting Protestant groups breaking with the established Church of England. The Quakers, especially the Valiant Sixty, sought to convert others by travelling through Britain and overseas preaching the Gospel. Some early Quaker ministers were women. They based their message on a belief that "Christ has come to teach his people himself," stressing direct relations with God through Jesus Christ and direct belief in the universal priesthood of all believers. This personal religious experience of Christ was acquired by direct experience and by reading and studying of the Bible. Quakers focused their private lives on behaviour and speech reflecting emotional purity and the light of God, with a goal of Christian perfection.Past Quakers were known to use thee as an ordinary pronoun, refuse to participate in war, wear plain dress, refuse to swear oaths, oppose slavery, and practise teetotalism. Some Quakers founded banks and financial institutions, including Barclays, Lloyds, and Friends Provident; manufacturers including the footwear firm of C. & J. Clark and the big three British confectionery makers Cadbury, Rowntree and Fry; and philanthropic efforts, including abolition of slavery, prison reform, and social justice. In 1947, Quakers represented by the British Friends Service Council and the American Friends Service Committee were awarded a Nobel Peace Prize.