Your eye shall not pity him, but you shall purge the guilt of innocent blood from Israel, so that it may be well with you.
It was one of the precepts given to the sons of Noah that whoso sheddeth man's blood by man shall his blood be shed, that is, by the avenger of blood, Gen 9:6. Now here we have the law settled between blood and blood, between the blood of the murdered and the blood of the murderer, and effectual provision made, I.
Commenting on Deuteronomy 19:1-13
Thou shalt not remove thy neighbour's landmark,.... By which one man's land is distinguished from another; for so to do is to injure a man's property, and alienate his lands to the use of another, which must be a very great evil, and render those that do it obnoxious to a curse, Deu 27:17.
Thine eye shall not pity him, but thou shalt put away [the guilt of] innocent blood from Israel, that it may go well with thee. (g) Then whoever pardons murder, goes against the word of God.