As I'm lead to understand, many of the words used such as "wrath" and "judgment" take on a new light in the spiritual understanding. Recall: Isaiah 55:8-9. For instance if we see the word "sorrow" we think of it like men understand the word: but the scripture says: 2 Corinthians 7:10. People tend to understand the words of God through the mind of men, thinking, "Well, God must do things like men do, so 'anger' and 'wrath' must mean, 'hurting people and doing terrible things'" but I believe this is an error of earthy understanding. The 'wrath of God' is more like, a father who says "I'm disappointed in you": it isn't 'mean' it is something that hurts, but its use is intended, not only as truth, but, to be effectual in causing change for the better.
When Jesus says something like "slay them before Me" (remember this is a parable; an allegory) we tend to think of it in a worldly manner, after the understanding of a man; but to be "slain" by God, is much like the crucifixion: it brings out the spiritual man. The Word of God "slays" the "old man" bringing forth the "new man" through teaching the Word.
Consider: Zephaniah 2:12 and Revelation 19:21. Now, we know that the Word of God is the "sword of the spirit": Ephesians 6:17 and that this sword: Hebrews 4:12 and causes transformation from a state of "sinner" into a state of "saint": 2 Corinthians 5:17 so when we see God talking about "slaying them with My sword" He is really spiritually talking about, killing the old man with the gospel, causing the rise of the new man.
So men look for "wrath" as being, sheets of literal fire and all the people screaming and literally in terror; while it really, spiritually means; men being convicted of sin, and repenting, and turning to God; becoming a "new creation": and so when we see "bring my enemies and slay them before Me" it is alluding to: Jeremiah 25:31, which sword is the Word of God, and this "slaying of enemies" is spoken of here: Hebrews 10:13 and fulfilled here: Philippians 2:10-11
So "slay My enemies before Me" is spiritually meaning "teach them without understanding the truth, and cause the old to pass away and to make them become new"