(AJC) — First Lady Michelle Obama spoke about community service, helping others and overcoming obstacles when she addressed 550 Spelman College graduates Sunday in College Park. ”Do big things,” she told her audience. “Now it’s your turn to repay the favor.” Obama delivered her keynote speech to 9,000 people in the ballroom of the Georgia International Convention Center, saluting the graduating class for one of the nation’s two historically black women’s colleges. “It is vitally important that you all rise to the highest ranks of every industry and every profession,” Obama said. “As you climb those career ladders, just remember to reach down and pull others up behind you.” Obama recounted how she took a high-paying job in the high-rise offices of a Chicago law firm. While she welcomed the paycheck, and paying down her student loans, she missed doing more fulfilling work.