Deuteronomy 19:13 in the King James Version
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.
Context
12 then the elders of his city shall send and bring him there, and deliver him into the hand of the avenger of blood, that he may die.
13 Your eye shall not pity him, but you shall purge the innocent blood from Israel that it may go well with you.
14 You shall not remove your neighbor’s landmark, which they of old time have set, in your inheritance which you shall inherit, in the land that the LORD your God gives you to possess.