people had been subverting slavery for centuries. slavery eventually got to the point where it was no longer in the north thanks to all the grassroots efforts culminating into some actual policy. later, in response to the threat of slavery expanding west, we end up with a massive war that kills lots of people. there was no thief in the night. there was abolition, slave rebellions, runaway communities in the north and in canada, etc.
all this happened gradually at a logical pace considering who the anti slavery coalition was and what their resources were at every step of american history, and culminated into the end of slavery. and quite frankly, if the end of slavery was a miracle, why couldnt god make the reconstruction era go better? god did not get rid of white supremacy or southern attempts at bringing back a sort of de facto slavery, and we are dealing with that even today.
and look at how christians talk about the hatian independence. they think the devil helped the hatians get free. i just suggest you really honor the sacrifices of your ancestors and do a little reading about the steps they and their allies took to get you free. the stuff you are saying is kind of insulting, quite frankly.