Prospective Republican presidential candidate Jeb Bush defended the place of Christian values in society during his commencement address at Liberty University, Virginia on Saturday.

In his address to the 34,000 people gathered at Liberty's football stadium, Bush lauded the power an active Christian conscience. "Whatever the need, the affliction, or the injustice, there is no more powerful or liberating influence on this earth than the Christian conscience in action," he said.

Quoting GK Chesterton, he said: "These are the days when the Christian is expected to praise every faith but his own."

Bush added: "He never accepted that limitation, and neither should we... One of the great things about this faith of ours is its daring, untamed quality, which is underrated."

The former governor of Florida spoke of the "bold challenge" of loving both our neighbours and our enemies, and said he could not think of "any more subversive moral idea ever loosed on the world than the last shall be first, and the first, last."

But he said this is often not the way that Chritsianity is seen in America. Bush cited a number of cases that, he said, showed religious freedom was under assault and considered by some to be an "obstacle to enlightened thought".

One was an attempt by President Barack Obama's administration to require businesses to include contraception coverage in their employees' health insurance as part of Obama's signature healthcare law.

The decision was challenged in court by two companies owned by Christian families who felt that providing contraception violated their religious beliefs. The Supreme Court ruled in favor of the businesses last June in a case known as Burwell v. Hobby Lobby.

"The progressive political agenda is ready for its next great leap forward, and religious people or churches are getting in the way. Our friends on the Left like to view themselves as the agents of change and reform, and you and I are supposed to just get with the program," Bush said.

But although some may think that Christianity is "static, narrow, and outdated," Christians can choose how they respond. "We can take this as unfair criticism, as it typically is, or we can take it as further challenge to show in our lives the most dynamic, inclusive, and joyful message that ever came into the world," he said.

Liberty University was founded by evangelist Jerry Falwell and is said to be the world's largest Christian university.

It has become a popular destination for presidential candidates keen to appeal to evangelical voters. Senator Ted Cruz launched his presidential campaign there in March and potential presidential candidate Louisiana governor Bobby Jindal gave last year's commencement address.

Bush, who converted to Catholicism in 1994, said he is sometimes asked whether he would allow his political decisions to be influenced by his Christian faith.

"Whenever I hear this, I know what they want me to say. The simple and safe reply is, 'No. Never. Of course not.' If the game is political correctness, that's the answer that moves you to the next round."

But he dismissed this view, adding: "The mistake is to confuse points of theology with moral principles that are knowable to reason as well as by faith."

Bush, whose father and brother both served as president, gave a strong hint as to his plans in saying he was happy to meet Jonathan Falwell, son of Jerry Falwell and brother of Liberty president Jerry Falwell Jr.

"His father used to be president, and then his brother became president. Somehow, I don't know what it was, we really hit it off," Bush chuckled.

This is not the first time Bush has sought to emphasise his Christian credentials. At the end of April he spoke at the National Hispanic Christian Leadership Conference about his personal faith and the importance of religious freedom in the US.

But there are a number of others competing for support from the Christian right. Former governor of Arkansas and ordained Baptist minister Mike Huckabee, former Pennsylvania Senator Rick Santorum and former Texas Governor Rick Perry are all competing for evangelical support seen as critical in Iowa and South Carolina, which will hold two early contests ahead of next year's November election.

Additional reporting by Reuters