Answer:
He said that slavery was against the laws of nature.
Step-by-step explanation:
Albert Barnes wrote the book entitled "The Church and Slavery," where he condemned slavery bravely. According to Barnes, the Christian should regard slavery as a bad and immoral thing, something that was against the will of God and against the laws of nature. In the book, he called for slavery to be treated as something hideous "like other sins and mistakes are."
Albert Barnes was an American theologian and abolitionist, pastor of the Presbyterian Church in Morristown, New Jersey and pastor of the First Presbyterian Church in Philadelphia.