One of the most sobering realities, one of the most sobering thoughts there is in the human experience is the thought of taking another life. And for so many people, and rightly so, this is a thought they can't even wrap their minds around. That's a murderer, somebody who takes another human life. And yet then we have murderers and we have the question, what do we do with them?
Well, the Bible is our only source of authority. And in Genesis chapter 9, God establishes with Noah and for all of humanity that one who takes the life of a human being in murder ought to have his life taken. And God actually establishes the death penalty.
The carrying out of the death penalty was actually the very first role of human government. to make certain that there is a God-ordained body of people that are given the right to take the life of one who takes other lives. So the Bible supports the death penalty, and so therefore we do as well.