"You shall not murder.” Exodus 20:13
God requires the death penalty for murder (Genesis 9:6), but how is the death penalty to be carried out?
God’s law requires two or more eye-witnesses of the crime and the witnesses are to be the first involved in executing the guilty party. Without such witnesses the guilty party may go free.
Deuteronomy 17:6-7 Whoever is deserving of death shall be put to death on the testimony of two or three witnesses; he shall not be put to death on the testimony of one witness. 7 The hands of the witnesses shall be the first against him to put him to death, and afterward the hands of all the people. So you shall put away the evil from among you.
Some might object, fearing that some who are guilty will go free. It is true that some guilty parties might. But God’s care for human life extends even to the guilty. From God’s perspective (and He knows that humans are incapable of being perfectly just all of the time), it is better than some who are guilty may go free than for an innocent person accused of murder be executed without sufficient due process.
Add to that, the fact that ultimate justice will be served in His court.
And do not miss that God says that capital punishment is a deterrent to crime—regardless of what opponents of capital punishment say!