At City College of New York, with nearly 4,000 graduates who represent 150 nationalities and speak more than 100 languages, First Lady Michelle Obama was right at home with diversity as the theme of her commencement address Friday afternoon.

“You represent about practically every possible background, every color, every station and walk of life, and you’ve taken so many different paths to this moment,” Obama told the graduates and the massive audience that spilled over the lawn of the newly designed south campus, despite the threat of rain. “Graduates, no matter where your journey started you all have made it here today through the same combination of unyielding determination, sacrifice and a whole lot of hard work.”

The cheers interrupted her repeatedly as she recounted the struggles each student endured to get to this level of his or her educational development. Obama said even with all the studying, holding down a job and taking care of the needs of family, “You found time to give back to the community, tutoring young people, reading to kids, volunteering at hospitals. You still managed to do prestigious internships and research fellowships.”

Obama expressed again and again the “glorious diversity” of the 2016 class, as well as how rewarding it was to be at City College because this would be her last commencement address as first lady.

“There is no better way to celebrate this country than being here with you,” she continued. “As all of you know, this city, for centuries, has been the gateway to America for so many striving hope-filled immigrants … and this school was the gateway to actually realizing that opportunity in their lives.”

In her recitation of the college’s history, Obama noted that this school was a place where students did not have to hide their last names, change their accents or put on any kind of airs. “The student selected here was based on merit, and merit alone,” she explained. “It is no accident that this school has produced 10 Nobel Prize winners, countless captains of industry, icons and leaders at the highest level of government. Because talent and effort combined with our various background and life experiences has always been the lifeblood of our singular American genius.”

Lyricist Ira Gershwin, former CEO of Intel Andrew Grove, Jonas Salk and Colin Powell were among the school’s notable alumni she mentioned to great applause. Along with the greats of the past she cited a few promising students from immigrant backgrounds who had excelled in the classroom, including the class’s salutatorian Orubba Almansouri, a native of Yemen.

Returning to her theme, Obama mentioned the comments of valedictorian Antonios Mourdoukoutas, who addressed the crowd before she spoke. “He said that he had learned that the diversity in human experience gives rise to diversity in thought,” she said. “I could not have said this better myself.”

It didn’t take too much imagination to know who she was referring to when she said, “There are some who view our diversity as something to be contained rather than a resource to be tapped. They tell us to be afraid of those who are different, to be suspicious of those with whom we disagree. They act as though name-calling is an acceptable substitute for thoughtful debate—as if anger and intolerance should be our default state rather than altruism and openness.”

She told the graduates and their families that she had traveled around the world and had seen what happens when such terrible ideas take hold. “I have seen how leaders rule by intimidation; leaders who demonize and dehumanize entire groups of people often do so because they have nothing else to offer. Graduates, that is not who we are.”

If her point was not clear, she said, “We do not build walls to keep people out because we know that our greatness has always depended on contributions from people who were born elsewhere … who have come here and made this country their home.”

Her message of diversity was evident throughout the crowd.