In God's eyes, without the blood of Jesus, we are all monsters.
1 But Jesus went to the Mount of Olives. 2 Early in the morning He came again into the temple, and all the people were coming to Him; and He sat down and began to teach them. 3 The scribes and the Pharisees *brought a woman caught in adultery, and having set her in the center of the court, 4 they *said to Him, “Teacher, this woman has been caught in adultery, in the very act. 5 Now in the Law Moses commanded us to stone such women; what then do You say?” 6 They were saying this, testing Him, so that they might have grounds for accusing Him. But Jesus stooped down and with His finger wrote on the ground. 7 But when they persisted in asking Him, He straightened up, and said to them, “He who is without sin among you, let him be the first to throw a stone at her.” 8 Again He stooped down and wrote on the ground. 9 When they heard it, they began to go out one by one, beginning with the older ones, and He was left alone, and the woman, where she was, in the center of the court. 10 Straightening up, Jesus said to her, “Woman, where are they? Did no one condemn you?” 11 She said, “No one, Lord.” And Jesus said, “I do not condemn you, either. Go. From now on sin no more.”]
John 8
Personally I'm not a fan of the death penalty. I don't take delight in someone dying. It's funny because most of my beliefs are pretty conservative but I guess I can always relate to the bad guy, which makes it easier for me to show mercy for them. I think about all the times God has allowed me to live when I deserved the death penalty. While I don't think capitol punishment is sin, since it's obviously biblical, I just know that God will serve justice when He chooses, whether that be through capitol punishment or something else.