The essay was written in 1774 and published March 8, 1775 when it appeared in the Pennsylvania Journal and the Weekly Advertiser. Just a few weeks later on April 14, 1775 the first anti-slavery society in America was formed in Philadelphia. Paine was a founding member.
That some desperate wretches should be willing to steal and enslave men by violence and murder for gain, is rather lamentable than strange. But that many civilized, nay, Christianized people should approve, and be concerned in the savage practice, is surprising; and still persist, though it has been so often proved contrary to the light of nature, to every principle of Justice and Humanity, and even good policy, by a succession of eminent men, and several late publications.
Our Traders in MEN (an unnatural commodity!) must know the wickedness of the SLAVE-TRADE, if they attend to reasoning, or the dictates of their own hearts: and such as shun and stiffle all these, wilfully sacrifice Conscience, and the character of integrity to that golden idol.
The Managers the Trade themselves, and others testify, that many of these African nations inhabit fertile countries, are industrious farmers, enjoy plenty, and lived quietly, averse to war, before the Europeans debauched them with liquors, and bribing them against one another; and that these inoffensive people are brought into slavery, by stealing them, tempting Kings to sell subjects, which they can have no right to do, and hiring one tribe to war against another, in order to catch prisoners. By such wicked and inhuman ways the English are said to enslave towards one hundred thousand yearly; of which thirty thousand are supposed to die by barbarous treatment in the first year; besides all that are slain in the unnatural ways excited to take them. So much innocent blood have the managers and supporters of this inhuman trade to answer for to the common Lord of all!
More here. (Note: At least one daily post throughout February will be devoted to African American History Month)