“Therefore as I live, says the Lord Yahweh, I will prepare you for blood, and blood will pursue you. Since you have not hated blood, therefore blood will pursue you.”
Edom have not hated the shedding of blood, but have delivered God's people to death. Therefore God will prepare blood for them, that is will arrange for their slaughter, just as they arranged for the slaughter of God's people. And this is guaranteed by the fact that God, the God whom they have opposed, is the living God. Notice the fourfold mention of blood. The word for blood is related to that for Edom (mentioned in Ezekiel 35:15), so this may be a deliberate play on words. But Edom were kin to Israel, and were therefore blood guilty.