Here is a biblical scholar's take on the subject:
"Jesus did support the death penalty and He left a hearty biblical record proving the point. Jesus has been so remade by the modern world into a mix of Mahatma Gandhi, Mother Teresa and Tiny Tim that they cannot see the Jesus clearly portrayed in the Bible. Let us look at the record.
"Consider this: the Mosaic Law very strongly supported the death penalty and Jesus never once disobeyed the law or taught against it. He said, Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil (Matt.5:17). The law made numerous provisions for the death penalty. Jesus did not come to destroy these provisions but to fulfill them. As such, He would have supported the death penalty."
And this on Paul, one of the Apostles:
"Paul recognized the justice of the death penalty. When he was brought before the judgment seat of Festus, he said, For if I be an offender, or have committed any thing worthy of death, I refuse not to die (Ac.25:11). By this, Paul admitted that there were offenses worthy of death and that the government had the right to administer death in those cases."
"He further states in Romans that the powers that be (government) are ordained by God. They act as ministers of God for good. He further warns, But if thou do that which is evil, be afraid; for he beareth not the sword in vain: for he is the minister of God, a revenger to execute wrath upon him that doeth evil (Rom.13:4). The powers that be bear the sword to execute wrath on those that do evil. What do you think these powers are going to do with the sword? Are they going to slap someone on the wrist with it? No. They are going to execute wrath by executing someone. They are going to administer the death penalty."
Link for rest of article:
http://www.learnthebible.org/death_penalty.htm