Faith leaders in Georgia have petitioned for a permanent stay of execution for Kelly Gissendaner, who was due to be given the lethal injection yesterday.

The 46-year-old was sentenced to death for plotting to kill her husband Douglas Gissendaner in 1997 with her boyfriend, Gregory Owen, who is serving life imprisonment for the murder.

She has since repented of her crime, come to faith and now counsels others in the prison.

Georgia clergy delivered a petition yesterday including the signatures of 500 faith leaders and 40 boxes of names from people supporting her case from around the world.

Yesterday afternoon the Georgia Supreme Court rejected Gissendaner's request for a stay of execution.

Her first execution date was February 25, but had to be postponed owing to bad weather. The second date – Monday evening – was also postponed because there were concerns about the drug to be used for the lethal injection. 

After the first postponement a Groundswell petition was launched calling to stop her execution altogether. It has since received more than 77,000 signatures.

Gissendaner's friends made a film in support of the campaign, speaking of how her life had been transformed by her faith in God.

Since being in prison Gissendaner has completed a certificate in theology and is seen as a pastoral figure to many in the prison.

11Alive news reports that the Gissendaner's three adult children were at the the prayer vigil at Emory University's William Cannon Chapel on Monday night.

Christian activist Shane Claiborne wrote on the Red Letter Christians website in support of the petition in a post entitled 'The Gospel of Kelly Gissendaner'. While acknowledging that many will say the situation is hopeless, and it is too late for a change in her penalty, he argued that there is precedent for a last-minute stay of execution.

Claiborne referred to the case of Billy Moore, whose execution in Georgia was stopped after support from faith leaders, including Mother Teresa, and the victim's family.

"Tonight there is an opportunity," Claiborne wrote, "not to be "soft on crime" or to ignore wrongdoing, but to bear witness that redemption is possible. Tonight GA leaders have a chance to recognize that people can be healed, rehabilitated, restored – and that they do not have to be forever held hostage and defined by the worst decision they made."

He continued: "Like Billy Moore, Kelly Gissendaner is the quintessential story of a life converted, transformed, saved by faith in Jesus... And her life is a sermon, a much-needed sermon in the heart of the Bible belt. The message is this – God so loved the world, that Christ came, not to condemn to the world but to save us (John 3:16).

"We were worth saving. And Kelly certainly was not saved in order to be executed – she was saved so that her life can be a witness of God's love and grace."

Gissendaner is due to be the first woman to be executed in the state of Georgia in 70 years. In 1945 Lena Baker was executed for killing her employer, but was posthumously pardoned in 2005 when it was recognised that she had killed him in self defence.