“America is great because America is good, and if America ever ceases to be good, America will cease to be great.”

Presidential campaign (April 12, 2015 – 2016), 2016 Democratic National Convention (July 28, 2016)
Source: "America is great because America is good" can be found in a contribution by Reverend Clarenca Reynolds to the September 6, 1922 https://books.google.com/books?id=3sYpAAAAYAAJ&pg=RA3-PT21 issue of the Herald and Presbyter. The line is sometime falsely attributed to Alexis de Tocqueville.
Context: We will stand up against mean and divisive rhetoric wherever it comes from. You know, for the past year, many people made the mistake of laughing off Donald Trump's comments – excusing him as an entertainer just putting on a show. They think he couldn't possibly mean all the horrible things he says – like when he called women “pigs.”Or said that an American judge couldn't be fair because of his Mexican heritage. Or when he mocks and mimics a reporter with a disability. Or insults prisoners of war like John McCain –a true hero and patriot who deserves our respect. At first, I admit, I couldn't believe he meant it either. It was just too hard to fathom – that someone who wants to lead our nation could say those things. Could be like that. But here's the sad truth: There is no other Donald Trump.... This is it. And in the end, it comes down to what Donald Trump doesn't get: that America is great – because America is good.

When asked if Donald Trump is racist.
Presidential campaign (April 12, 2015 – 2016), Democratic Presidential Debate in Miami (March 9, 2016)
Context: I was the first one to call him out. I called him out when he was calling Mexicans rapists.... His demagoguery, his trafficking in prejudice and paranoia has no place in our political system. Especially from somebody running for president who couldn’t decide whether or not to disavow the and David Duke. So people can draw their own conclusions about him. I will just end by saying this. You don’t make America great by getting rid of everything that made America great. I think it’s un-American. I think what he has promoted is not at all in keeping with American values.

Presidential campaign (April 12, 2015 – 2016), Speech in Warren, Michigan (August 11, 2016)

Dorothy Gish
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citation needed
The Late Late Show with Craig Ferguson (2005–2014), Commonly repeated

2016, DNC Address (July 2016)
Context: America is already great. America is already strong. And I promise you, our strength, our greatness, does not depend on Donald Trump. In fact, it doesn’t depend on any one person. And that, in the end, may be the biggest difference in this election — the meaning of our democracy.
Ronald Reagan called America “a shining city on a hill.” Donald Trump calls it “a divided crime scene” that only he can fix. It doesn’t matter to him that illegal immigration and the crime rate are as low as they’ve been in decades — (applause) — because he’s not actually offering any real solutions to those issues. He’s just offering slogans, and he’s offering fear. He’s betting that if he scares enough people, he might score just enough votes to win this election.
And that's another bet that Donald Trump will lose. And the reason he'll lose it is because he’s selling the American people short. We're not a fragile people. We're not a frightful people. Our power doesn’t come from some self-declared savior promising that he alone can restore order as long as we do things his way. We don’t look to be ruled. Our power comes from those immortal declarations first put to paper right here in Philadelphia all those years ago: We hold these truths to be self-evident, that all men are created equal; that We the People, can form a more perfect union.
That's who we are. That’s our birthright — the capacity to shape our own destiny.

President Bill Clinton — reported in Seth Borenstein (July 23, 1998) "Astronaut Filled America's Need for a Space Hero", Detroit Free Press, p. 1A.
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On his play The Chickencoop Chinaman (as quoted in the book Notable Asian Americans http://smithsonianapa.org/wp-content/uploads/sites/8/2009/10/chin-frank.pdf)