John Locke had some faith in a God as he did not deny the humanity of any soul. He may have mentioned that slaves were prisoners of war and if they were capable of causing or fighting wars and of making contracts of sale of such prisoners with other contracting parties, then they were human and capable of communicating price with terms and some discussion of acceptance, offer and consideration. On some other future occasion, the previous prisoners of war may have turned around and conquered those who had vanquished them previously. The prisoners or their tribe will have become the sellers of the conquered in battle. Your father will explain his history to you and his inability to overcome his introverted tendencies or self-retribution if he has these qualities of self-loathing. The Hebrews in Egypt provided much inspiration for early christian hymns. The apostle Stephen was stoned in peace and John Locke was a determined reader of history, the bible and humanity who suffered some failings when a tractor or cotton gin would have saved many a conscience if they did not fail to employ that technology. He also concluded that the pursuit of Life, Liberty, Health and Property is the purpose of EL-Shaddai as Master, Chief goal and singular Aspiration of any enlightened political union or civil society under the rule of good, balanced and enforceable law that does not contain alibis for aggressors with courts, evidence, trials and penalty. Crispus Attucks will have read this in a book or a newspaper of his day. I am quite sure. He was a free citizen of the empire and commonwealth.