Some of the first Christian opponents to slavery came from Non-Conformist congregations eg Quakers, Methodist and Presbyterians. When the Society for the Abolition of the Slave Trade was formed in 1787, nine of its 12 original members were Quakers.
The main thrust of Christian abolitionism emerged from the evangelical revival of the 18th century. It was based on its beliefs on morality and sin. John Wesley, the founder of Methodism, questioned the morality of slavery. This influenced many Christian abolitionists including the former slave trader turned clergyman, John Newton.
Evangelical Christians included Thomas Clarkson, William Wilberforce and Granville Sharp. Clergymen such as James Ramsay who had worked in the Caribbean were also influential in exposing the facts of plantation slavery.
From the mid-18th century a new set of church leaders challenged the complacency of previous generations. Beilby Porteus, Anglican Bishop of London, seriously questioned the Church’s stance on slavery. The Scots William Robertson and James Beattie both influenced Wilberforce. Scottish churches were amongst the key drivers in the abolitionist movement, although the Church of Scotland did not petition Parliament to end the slave trade.
At home the British heard about the treatment of slaves from missionaries in the colonies. The Christian doctrine that all people were equal in the eyes of the Lord went against the argument for slavery.