Show no pity to the evil things

Deuteronomy 19:1-21
Set aside three cities centrally located in the land the Lord your God is giving you to possess. Cities of Refuge
The rule concerning the man who kills another and flees there to save his life - one who hills his neighbor unintentionally, without malice aforethought.
If the Lord your God enlarges your territory as he promised ad gives you the whole land, then you are to set aside three more cities.
But if a man hates his neighbor ad lies in wait for him, assaults and kills him, and then flees to one of these cities, the elders of his town shall send for him, bring him back from the city, and him her over to the avenger of the blood to die. Show no pity.
Do not move your neighbor's boundary stone set up by your predecessors in the inheritance.
If a malicious witness take the stand to accuse a man of a crime, the judge must make a thorough investigation, and if the witness proves to e a liar, then do to him as he intended to do to his brother. Show no pity.
Why?
Must purge the evil from among you for the Lord is holy.
City of refuge like a savior Jesus, give innocent people a chance to flee away from the avenger of blood.
How?
Show no pity to the evil things.