According to the Principle of Creation, man is created to deal with only one master. Adam was in a position to deal with two masters, God and Satan. Therefore, God could not work His providence with such a man. If God could deal directly with fallen Adam, and with his offerings, then Satan could also claim he had a basis to deal with Adam and his offering because of their blood relationship. But with Adam still having two masters, God would not be able to work His providence.