of Blood.

http://www.theempoweredchristian.com/of-blood..html

God leaves man for the first one thousand years and then makes a radical decision, to destroy all except a remnant of man. This for one reason. To prevent the complete infection, tainting of the human blood by the anti-spirits of God. For the sons of God produced a mutated human race by mixing with women. God wants no mixing of the blood except with it’s own kind. The blood is what makes us, not the body. The enemy knows just how critical is the physical blood to the Spiritual life of God’s people and seeks to do everything to make it impure. God has no choice but to wipe out every human abomination and start over. When God makes a plan, He seeks to always fulfill it.