Dylann Roof was told he will face death for killing nine black church members during Bible study in a racially motivated attack in South Carolina.
The attacker specifically picked out Emanuel AME Church, the South's oldest black church, to carry out the cold, calculated slaughter, Assistant US Attorney Jay Richardson said.
The 12 people Roof targeted opened the door for a stranger with a smile, he said. Three people survived the attack.
His sentence has reignited the debate on the death penalty with conflicting views on whether it is Biblical.
Recording Clerk for Quakers in Britain Paul Parker said Jesus was clear on this issue.
"There is something of God in everything human being and that all human life is sacred and that no person, whatever they've done, is utterly lost," he stressed on Premier's News Hour.
"However deeply somebody may have transgressed, there's always the hope of recovery and of redemption.
"By putting him to death he becomes a kind of martyr for a cause and that to me is at least as dangerous as keeping him alive."
"Keeping him alive allows the possibility that he may change, that he may see the mistakes that he has made."
But Mark Mullins, a Christian barrister who supports the death penalty, told Premier: "The Lord set down this sentence to be passed over all mankind, that if you shed another person's blood and they die then your blood should be forfeited.
"That is a proportionate sentence and recognises that we're all made in the image of God.
"It sends the message that life is to be valued above everything else in this world.
"When you do not punish murderers, commensurate with the seriousness of the crime, then you devalue life."
Listen to Premier's Antony Bushfield speaking to Paul Parker on the News Hour:
Listen to Premier's Aaron James speaking to Mark Mullins:
