So, it's going to happen: white supremacist Dylann Roof will die for his murder of nine people at Emanuel African American Episcopal Church in Charleston in June 2015.

The jury had the option to recommend life in prison without parole, but chose not to: Roof, they said in a unanimous verdict, deserved to die.

Perhaps we should say, "It's probably going to happen." The path from the dock to the lethal injection chamber is long and winding in the US justice system, and Roof has only just taken his first step. But 12 jurors have waved him on his way.

I don't believe in the death penalty, for anything. I think it's useless, a hangover from a primitive idea of justice that evolved from the need to limit revenge in pre-modern times. I think the state should punish, but punishment should always leave open the possibility of repentance and reform – and that's not the same as saying there should always be the possibility of release.

The clinching argument against the death penalty is that it shuts that down forever. As Clint Eastwood's character Will Munny says in Unforgiven: "It's a hell of a thing, killin' a man. Take away all he's got, and all he's ever gonna have."

That includes the possibility that he might change and meet with God, and it's not something we should do unless we absolutely have to – and we don't.

But the Clint Eastwood connection is instructive, too. His typical screen character is someone who doesn't care how many bad guys die. They deserve it. This is a truly primitive morality – the good must live, the bad must die. And the vast popularity of this kind of binary distinction between good and evil says something about how we are hard-wired to desire justice.

I feel it too. No, I don't believe in the death penalty. I wish Roof could have a life long enough to bring him to remorse and repentance. But if and when he is executed I expect to feel at best indifferent, at worst vaguely satisfied. He did a terrible, terrible thing with his eyes wide open, and there's no excuse for that. I don't sympathise with him, any more than I sympathise with Norwegian mass murderer Anders Breivik, another white supremacist who killed 77 people in 2011. Breivik is complaining his human rights are being breached because he's kept in solitary confinement. There are other cases I read about where people have done terrible things to innocent people, and my first reaction is to want the perpetrators to suffer and die.

And the shatteringly humbling thing about the Dylann Roof case is that so many of those whose lives he has utterly wrecked have rejected that desire for revenge. They, with so many more reasons to desire the ultimate revenge, have said they don't want him to die. They have faced down that primitive urge to hurt and destroy, because they have listened to the voice of Jesus who said, "Love your enemies." It's impossible not to think that their witness should have weighed more with the jury than it did. 

It's this example, more than any of the coolly rational arguments against capital punishment deployed by detached observers like me, that could really shift the terms of the debate. These are people who've felt the effects of violence intimately, and have responded with grace and forgiveness. It arises from their Christian faith, but it also arises from their experience as part of the black community; a University of South Carolina survey conducted last spring, found only 31 per cent of black South Carolina residents wanted him executed, against some 64 per cent of whites. The difference reflects the deep-seated antipathy to capital punishment that has grown up among many black people because of how it has been used as a tool of oppression against them. But this sense of outrage at the injustice toward their own community has translated into a rejection of the injustice involved in the state taking any life.

It's this gut feeling that capital punishment is wrong, even in such a deserving case as Dylann Roof's, that needs to be nurtured and shared so that it becomes unthinkable that the state would put someone to death. But that won't happen unless it's driven not by a denial of justice, but by an assertion of it. We want, above all, an acknowledgment of the value of those who have died. Killing the one who murdered them is a way of doing that, but it's not the only way. In the name of Christ, many of the bereaved of Charleston have chosen the harder road.

The jurors who found for the death penalty chose not to listen to them. But that witness speaks far more loudly than their verdict. The verdict was for death. The witness was for redemption, forgiveness and grace.

When Cain murdered his brother Abel, God said to him, "Listen! Your brother's blood cries out to you from the ground" (Genesis 4:10). It cries out for revenge. It's that voice the jurors heard.

The sprinkled blood of Christ "speaks a better word than the blood of Abel" (Hebrews 12:24). It cries out for reconciliation. The bereaved of Charleston chose to hear the voice of Christ.  

Follow Mark Woods on Twitter: @RevMarkWoods