Citing personal heroes Martin Luther King Jr., Presidents John F. Kennedy and Jimmy Carter, and the late Steve Jobs, Apple CEO Tim Cook Sunday told George Washington University graduates the world is theirs "to change." Cook spoke of the importance of personal values and finding work with meaning during the ceremony on the National Mall in Washington.

"This is your world to change," Cook told the estimated crowd of 25,000, Business Insider reported.

"Steve was an idealist," Cook said of Jobs, one of the co-founders of Apple and the visionary who guided the company. "He convinced me that if we worked hard, and made good products, we too could change the world.

"I took the job, and it changed my life,” Cook said. “It has been 17 years, and I have never once looked back.”

Cook described his teenage years in Alabama and recalled meeting then-Gov. George Wallace, who opposed desegregation. “Meeting my governor was not an honor for me,” Cook told the crowd. “Shaking his hand felt like a betrayal of my own beliefs. It felt wrong, like I was selling a piece of my soul.”

In contrast, Cook spoke of his respect for King, whom he described as one of his childhood heros, saying the civil rights leader "challenged Americans to make real the promise of democracy." He then turned his attention to Carter.

“Carter was kind and compassionate. He held the most powerful job in the world, and had not sacrificed any of his humanity,” Cook said.

Cook emphasized Apple's core values of using technology to better the world, and said it was Jobs who taught him that. He even said that the smartphone camera allows people to document injustice.

“People who witness injustice and want to expose it -- and now they can, because they have a camera in their pocket all the time.” 

Cook, who came out as gay last year, provided moments of levity as well. Again referring to smartphones, in this case, the iPhone, Cook joked: "Those of you with an iPhone, just place it in silent mode, and those of you who don't have an iPhone, please pass it to the center aisle. Apple has a world-class recycling program."