In his first ever visit to the United States, Pope Francis took the opportunity to tell President Barack Obama and the American public how important it is to preserve religious freedom, even saying that it is one of America's most "precious possessions."

"With countless other people of good will, [American Catholics] are likewise concerned that efforts to build a just and wisely ordered society respect their deepest concerns and their right to religious liberty," he said while addressing Obama at the White House in Washington, D.C. "That freedom remains one of America's most precious possessions."

According to the Catholic News Agency, Pope Francis echoed the appeal made by US bishops regarding the issue of religious freedom. He further told Obama: "All are called to be vigilant, precisely as good citizens, to preserve and defend that freedom from everything that would threaten or compromise it."

The pontiff lauded the role played by 70 million American Catholics in the preservation of religious freedom, since they helped build a tolerant and inclusive society, all the while "rejecting every form of unjust discrimination."

Pope Francis' words could not have come at a more opportune time, since the US is currently witnessing religious discrimination and unrest. One of the factors fanning faith-based disagreement is Obama's 2012 Health and Human Services (HHS) mandate, which requires institutions to provide contraceptive services, even if this goes against the religious beliefs of some institutions.

Moreover, the US Supreme Court recently issued a ruling legalising same-sex marriage throughout the country. This has been met with ringing denunciation by Christian and conservative leaders. Some judges are refusing to officiate same-sex marriages, explaining that to do so would be in violation of their faith. Bake shop owners and florists who have refused to serve gay couples are also experiencing the same form of religious discrimination.

Pope hails Obama's move on climate change

Pope Francis also highlighted the issue of climate change in his speech, lauding the Obama administration's efforts to seek solution to the problem of air pollution. "Accepting the urgency, it seems clear to me also that climate change is a problem which can no longer be left to a future generation," he said, adding that this is a "critical moment in history" with regards to caring for our "common home."

The Pope said the changing climate requires people to take action now so that future generations would still have a safe environment to grow up in.

"I would like all men and women of good will in this great nation to support the efforts of the international community to protect the vulnerable in our world and to stimulate integral and inclusive models of development, so that our brothers and sisters everywhere may know the blessings of peace and prosperity which God wills for all his children," he said.

Pope addresses concerns on accepting migrants

Another area of concern the Pope tackled during his audience with US bishops in St. Matthew's Cathedral in Washington, D.C. was the worldwide migrant crisis. He called today's migrants and refugees as "pilgrims."

Pope Francis said he understands that many are apprehensive about accepting a large influx of foreigners, but he said people should try to look beyond the differences they have with others.

"Do not be afraid to welcome them. Offer them the warmth of the love of Christ and you will unlock the mystery of their heart. I am certain that, as so often in the past, these people will enrich America and its Church," he assured.

He said the primary reason of his visit is to fight for the cause of life and family, and this is why he is thankful of the Catholic Church in the US for its commitment to integrate immigrants to American society.

He encouraged bishops to be "shepherds who do not lower our gaze, concerned only with our concerns, but raise it constantly toward the horizons which God opens before us and which surpass all that we ourselves can foresee or plan."

California missionary Junipero Serra canonised

The Pope was extremely busy during his first day in the US, since he also canonised California missionary Junipero Serra as a saint during his mass at the Basilica of the National Shrine of the Immaculate Conception. It was attended by over 25,000 people.

The Pope lauded Serra as a kind and open-hearted man who defended Native Americans from colonisers. "He was excited about blazing trails, going forth to meet many people, learning and valuing their particular customs and ways of life," he said. "Junipero sought to defend the dignity of the native community, to protect it from those who had mistreated and abused it. Mistreatment and wrongs which today still trouble us, especially because of the hurt which they cause in the lives of many people."

Serra was a Spanish Franciscan friar who founded a mission in Baja, California, and the first nine of 21 Spanish missions in California from San Diego to San Francisco. He was beatified by Pope John Paul II on Sept. 25, 1988.