The partial separations that intermediate judgment bring about, are meant to serve as a warning to the unrepentant. In the story of the Flood God separated the righteous (Noah and family) before executing His judgment. Turn with me to Exodus 8. During the course of the ten plagues in Egypt, this differentiation emerges before God executes the plague of the flies. God told Moses to tell Pharaoh about this difference.
God makes a difference. This will become a large portion of what I am going to be saying in this sermon. God is making a difference between His people and those who are part of the world.