So the Bible seems to opt for mercy in the face of violence and it calls for justice, meaning the absence of special privileges for those with more resources. On those two realities it seems to push us as witnesses against the use of the death penalty. One final reminder is that ever present reality that innocent people will and have been caught in this web of violence. At least 25 people have been executed in this century who it was later proven were in reality innocent. Twenty-five people who did not deserve the punishment they received who were unable to reclaim life.
Evidence also indicates that each year at least one innocent person is convicted of murder.
We do not and often cannot know for certain at the moment who that person is. The death penalty does not allow for mistakes to occur. Jesus has called for his followers to be witnesses of these things. One of the calls in today's world is for the witnesses of these things to speak out on the topic of violence and the state's response to that violence with the penalty of death. The Biblical record is on the side of mercy and justice.