Jesus poses a particular challenge to Dawkins' theory that religion fuels violence, McGrath continued. He pointed to the example of Jesus Himself, who did not perpetrate violence, but instead had violence committed against Him.
He also highlighted the forgiveness of the Amish community after five schoolgirls were shot dead by a lone gunman in a tiny schoolhouse in Pennsylvania in 2006. The cycle of violence, was in this case, "broken before it began", he said.
"Believing in this God is a disincentive to violence," he said.
McGrath reassured Christians that they had "nothing to fear from this book". If anything, it presents a "challenge to go deeper in your faith by engaging in the agenda Dawkins has raised", he told the audience.
Campolo, meanwhile, challenged the audience to "do what Jesus would do" and sponsor a child in poverty.
"The church is the only club in the world that exists for the benefit of non-members," he said. "If your commitment to Christ cannot translate into 60p a day for a kid in a Third World country you need to start asking yourself some very serious questions about what your commitment is all about.
"Is it just believing in doctrinal truths or is it doing what Jesus would do if he was in your place? Is it just believing in doctrinal truths or are you ready to surrender to the Holy Spirit and let the Holy Spirit invade you and create within you the sensitivity that will see Christ's suffering in those who are in need?"
Arts and drama also featured high on the programme, with full house performances of hit Christian pop opera Luv Esther, the Bollywood-style His Story, Hope Academy - the finale of a nationwide Christian music talent search, top US Christian band Salvador, Ben Cantalon and Soul Survivor.
The Week of Prayer for Parliament and Government, meanwhile, culminated in a prayer walk taking Christians to key parliamentary sites for prayer.
Pentecost Festival wraps up on Sunday with contributions from the Archbishop of York, Dr John Sentamu, and the President of the Methodist Conference, Martyn Atkins.
