From the South Lawn of the White House Wednesday, President Obama welcomed Pope Francis on his very first visit to the United States. As both addressed the 15,000 gathered, immigration and climate change action were key issues mentioned.

"You remind us that 'the Lord’s most powerful message' is mercy," Obama said to the Pope in his opening remarks. "That means welcoming the stranger with empathy and a truly open heart – from the refugee who flees war-torn lands, to the immigrant who leaves home in search of a better life."

"And, Holy Father," Obama continued, "you remind us that we have a sacred obligation to protect our planet – God’s magnificent gift to us. We support your call to all world leaders to support the communities most vulnerable to a changing climate and to come together to preserve our precious world for future generations."

As Pope Francis took the podium, he immediately launched into the importance of recognizing that immigrants built the United States, using his own life as an example:

Mr. President, I am deeply grateful for your welcome in the name of all Americans. As the son of an immigrant family, I am happy to be a guest in this country, which was largely built by such families. 

He also sided with the president on climate change, thanking him for all he is doing in the battle. In the process, Pope Francis managed to co-opt a quote from Martin Luther King's "I Have a Dream" speech on civil rights with the intent of emphasizing the importance of leaving a planet intact for future generations:

Mr. President, I find it encouraging that you are proposing an initiative for reducing 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. When it comes to the care of our “common home”, we are living at a critical moment of history. We still have time to make the changes needed to bring about “a sustainable and integral development, for we know that things can change” (Laudato Si’, 13). Such change demands on our part a serious and responsible recognition not only of the kind of world we may be leaving to our children, but also to the millions of people living under a system which has overlooked them. Our common home has been part of this group of the excluded which cries out to heaven and which today powerfully strikes our homes, our cities and our societies. To use a telling phrase of the Reverend Martin Luther King, we can say that we have defaulted on a promissory note and now is the time to honor it.

For his efforts on these issues, President Obama praised the Pope as one who has "set a profound moral example" in not only words, but deeds.