The separation of poor whites and enslaved blacks had come into some question before Bacon's Rebellion. In 1640, there is a clear law excluding blacks from owning any arms. 1662 deemed slavery a lifetime sentence (1) There are free blacks in the colonies however. There is an issue during this time regarding whether or not Christianity excluding a person from slavery. There is a clear rift before 1676 but it is clear that Virginia began to see the trouble with allowing blacks and poor whites to gather. In 1680, blacks were not allowed to gather in public places even funerals. Nathaniel Bacon combined both of these persecuted people could be gathered together to fight together. Virginia saw this threat and shut it down with harsher laws against enslaved blacks. If you wish to see the progression of slavery, I suggest the book by Peter Kolchin titled "American Slavery, 1619-1877"