Regarding the death penalty, the Bible says two things in particular.
"An eye for an eye and a tooth for a tooth."
However, Jesus summarized the 10 commandments into two great commandments, which are: "Love the Lord thy God with all thy heart, thy soul, thy mind and thy strength, and love thy neighbor as thyself."
The 10 Commandments do not include a command to murder those who murder, it only says "Thou shalt not murder." It says nothing about punishment for crime in the 10 commandments.
Some say the Death Penalty is a deterrent to crime. I do not believe it is. I just don't think someone who murders someone stops to think, "Well, if I don't kill them I will get a life sentence at worst. However, if I kill them I will get the death penalty." Someone capable of taking another's life does not value their own. How can the threat of death be a deterrent to a murderer. Especially with lethal injection. Maybe the thought of being literally fried in an electric chair could have deterred some. The death penalty today is the equivalent of going into surgery and getting knocked out, only you never wake up, compared to the older days.
In the movie "The Life of David Gale" a quote is made that all major religions denounce the death penalty. Did we think that all of the horrific murders in our country would cease after the Supreme Court began allowing the penalty of death again. Just two months ago, just 1.5 miles from my home, four young men ages 17-20 walked into a liquor store and robbed it and killed the two clerks on duty execution style. The police called it a "thrill killing" because the clerks had no weapons and were instructed to cooperate with any attempts at robbery. Do you think these four youths thought about whether or not they would get the death penalty. Did the fear of the death penalty affect their decision to shoot these two men, who did not resist, in the back of their heads. Just this past week 2 men robbed a restaurant in Texarkana after closing. They killed all three employees, one of which was a woman who was about 8 months pregnant. I wonder if they were intimidated by the possibility of the death penalty. These were younger men also, ex-employees of the restaurant, of which one had been fired 4 weeks earlier. I don't think they thought about the death penalty before pulling those triggers - what do you think?
Makes you wonder.