"When we talk to you about the 2014 elections..that's what's at stake,'' she said. "We cannot forget that."
"We need to ask ourselves whether we will have leaders in congress who share our values,'' she said.
"That is why the midterm elections are so critical,' she said, adding that she will continue to travel the country "talking about the midterms, galvanizing energy and passion."
Mrs. Obama said that she wants to support values that say "if you're wiling to work for it..you should be able to build a better life for your kids, our kids.''
Of course, she said, no one should "get a free ride,'' but Americans should also remember -- "There but for the grace of God go I."
"Any of us could lose the job we count on to support our family..and when that happens, it shouldn't mean falling off the cliff...not here in the United States of America ... that's not who were are."
More from the First Lady:
"We also believe that we should give everyone a fair shot,'' she said. "And that's certainly the kind of security..that I know so many of you grew up with."
"My family wasn't rich, far from it,'' she said. But she said she had "decent public schools,'' a supportive family, and her father had a good job.
"So I was able to get a college degree and go on to law school."
"For a working class kid from the South side of Chicago, being able to get my education meant everything to me...it was the foundation of my career. it was the launching pad for my dreams."
Today, there are so many kids out there, just like me, just like Barack..with such big dreams and so much promise -- kids who will never get those opportunities."
"For so many of these kids, no one is willing to invest in them,'' she said. "No one helps them shape a vision for what their lives could be with a decent education...and what's even worse is that when we fail to invest in our young people...it limits our country's future as well."
She said every day she thinks about "the millions of kids who fall through the cracks of opportunity" in this country.
"My story can be their story, if we give those kids a chance,'' she said.
She said she and the president will work to help more kids get to college, "so that they can pass on that gift of opportunity to their kids."
But she added:
"Barack cannot do all of this alone, just sittin' by himself in the Oval Office. It's a lonely place,'' she said to laughs.