For some time I've been pondering this cry of the Psalmist in a well-known Psalm excerpts of which are popular topics and appear on posters / fridge magnets. But, I don't recall ever hearing this part being preached on.

If You would only slay the wicked, O God, and the men of blood depart from me.
They speak against You wickedly, Your enemies who misuse your name.
Do I not hate them, O Lord, who hate you? Am I not grieved and loathe those who oppose You?
I hate them with perfect hatred; they have become my enemies.
Psalm 139:19-22

This is a Psalm of David and the mention of men of blood brings to my mind the political intrigues of his reign with the deaths of Abner (2 Samuel 3), Ish-Bosheth (2 Samuel 4), Ammon (2 Samuel 13), Absolom (2 Samuel 18), Saul's sons (2 Samuel 21) and David's complex relationship with Joab. Blood is what Joab is best remembered for, see David's instructions to Solomon in 1 Kings 2.

So David starts with a complaint, life in politics is not easy! Then He reminds the Lord that if nothing is done the Lord's reputation is at stake. They have become David's enemies, but how can he be free from them? I can imagine that thought burning in Davids mind.

We see a similar cry for revenge in Revelation 6:9-11. In context this is the cry of martyrs, but it is echoed in the inward groan of all the saints Romans 8:23. The cry of 'when will you judge?'. The response is 'wait a little longer, until the full number...' which reminds me of 2 Peter 3:9. God waits because He does not want anyone to perish. In John 3:16-21 we find out that 'God loves..., God does not want to condemn ...'. God wants everyone saved, but the big question is 'what do you want?'. Do you want darkness or light?

So, back in Psalm 139 in the context of David's cry / rant we read this.

O Lord, you have searched me and you know me.
You know my downsitting and my uprising; You perceive my thoughts from afar.
You sift and search out my path and my lying down and you are acquainted with all my ways.
Before a word is on my tongue, O Lord, You know it altogether.
...
Search me. O God, and know my heart! Try me and know my anxious thoughts!
See if there is any wicked / hurtful / offensive way in me, and lead me in the way everlasting.
Psalm 139:1-4; 23-24

The Psalm ends on the same theme with which it began 'Search me, know my thoughts'. Thoughts about those 'men of blood', anxeties arising from the complexities of the political arena.

He ends by praying for a clean heart (Psalm 51:10), a renewed mind (Romans 12:1-2), a mind free of thoughts which are offensive to God. A mind which has eternities values in view.

So how should I pray about the wicked, the men of blood? Jesus told us to love and pray for them Matthew 5:43-48. He told us that our behaviour towards them should be consistent with how our Heavenly Father treats them. This is not a new commandment from Jesus, He is reminding us of Exodus 23:4-5.

If you meet your enemy's ox or his donkey going astray, you should bring it back to him. If you see the donkey of one who hates you lying down under its burden, you shall refrain from leaving him with it; you shall rescue it with him.

In modern parlence 'if you see your enemy's wallet...'!

In recent days we have seen the UK government relinquish its responsibility to restrain evil with plans to further legalise murder (with safeguards!) in certain circumstances. Blood boils and one starts praying like David 'If only you would...' in Psalm 139:19-22. Both sides of the argument are coming from a culture where 'everyone does as they see fit' (Judges 21:25).

Psalm 139 addresses legalised murder (abortion & euthenasia) before David does his rant about 'the men of blood'.

You created my inmost being; you knit me togther in my mother's womb.
...
My frame was not hidden from you when I was made in the secret place.
When I was woven together in the depths of the earth,
your eyes saw my unformed body,
All the days ordained for me were written in your book
before one them came to be.
Psalm 139:13-16

Are my anxious thoughts on these matters offensive? Psalm 139:23-24.

In Phillipians 4:6-8 we are reminded:

Do not be anxious about anything, but in everything by prayer and perition, with thanksgiving, present your requests to God. And the peace God, which transcends all understanding will guard your hearts and your minds in Christ Jesus.

Finally, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable - if anything is excellent or praiseworthy - think about such things.

i.e. Turn your eyes upon Jesus, look full in His wonderful face and the things of earth will grow strangely dim in the light of His glory and grace.

Search my anxious thoughts, O God, and see if there is any offensive way in me!