Whatever thoughts [Newton] had about the legitimacy of the slave trade, he kept them to himself during his years at Olney, possibly erring on the side of caution because he knew that any public pronouncement would go on record and he would have be sufficiently convinced to be able to defend it. It would be against his interests to sermonize on provisional judgements.
He must have been aware of the debate about slavery, particularly as some of the trade’s most vociferous opponents were Christians. In 1757, the Member of Parliament for Hull, David Hartley, introduced a debate in the House of Commons as to whether the slave trade was ‘contrary to the laws of God and the rights of men.’ In 1769, Granville Sharp, who was to become one of the most prominent abolitionists, published ‘A Representation of the Injustice and Dangerous Tendency of Tolerating Slavery in England.’ In 1774, John Wesley, who had read Newton’s autobiography several times, produced his polemic, ‘Thoughts on Slavery.’
Newton was also aware of Selina Hastings, Countess of Huntingdon, an evangelical aristocrat devoted to spiritual and moral reformation. She had become a Christian after hearing Whitefield and was then herself responsible for the conversion of Lord Dartmouth. Well bred and wealthy, she was passionate about using her influence and money to spread the gospel, educate Christian ministers, and relieve suffering and injustice.
Inspired by her Christian faith, Countess Huntingdon was more concerned about individual dignity and national justice than the dangers of crossing barriers of class and race. In 1765 when it was common for an educated English person to describe Native Americans as ‘savages,’ she sponsored a tour of Britain by Samson Occum, a converted Mohegan from Connecticut involved in land rights issues and raising money for charity schools. He came to Olney and preached at St Peter’s and St Paul’s.
Newton was impressed with Occum, and what particularly struck him was that despite their racial and cultural differences their experience of conversion was identical. ‘In describing to me the state of his heart when he was a blind idolater [he] gave me, in general, a striking picture of what my own heart was, in the early part of my life.’
From chapter 6 of Amazing Grace – John Newton, slavery, and the world’s most enduring song, published by 2002