Christianity was institutionalized in the 4th Century BC as the official religion of the Roman Empire. People were punished in various ways and in various degrees for over a thousand years after that date. The fact that Jesus lied in a time when slavery was common and never once spoke out against it seems to suggest that he was unconcerned with the injustice of slavery. The average Hebrew on the street might be forgiven this omission, since slavery WAS the custom, but Jesus was God, or so it is claimed. He was far more concerned with the unfair exchange rate by merchants outside the Temple of Roman money (unholy, because it had Caesar's face on it, and Caesar claimed to be a god) and Jewish money.
From the beginning of Colonial times until after the Civil War, many books were printed and circulated teaching that slavery was actually beneficial to the slaves, because Jesus said, "For what shall it profit a man, if he shall gain the whole world, and lose his own soul?" This was interpreted to mean that in return for three or four decades of chopping tobacco and picking cotton, a slave would become a Christian and therefore would be rewarded in the Kingdom of Heaven. (Probably an equal but surely a separate part of Heaven, I imagine.)
The idea that each person had one soul of equal value, a concept most common to the Quakers and other religious dissidents did have a lot to do with the end of slavery. Of course, Gen. Simon Bolivar, Gen. José de San Martín and Padres and Morelos and Gen.Vicente Guerrero all abolished slavery in the Latin American Wars od Independence. In the American Revolution, who promised freedom to the slaves? The British, of course.
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