DENVER, Colorado (CNN) -- Michelle Obama took center stage at the Democratic National Convention on Monday night, stressing her love for the nation and making her case for why her husband should be the next president.

Michelle Obama says Barack Obama embodies the "hope" to lead America as its next president.

"I come here as a wife who loves my husband and believes he will be an extraordinary president," she said of her husband, Sen. Barack Obama of Illinois, the presumptive Democratic nominee.

Michelle Obama -- who could be the nation's first African-American first lady -- pushed a theme of unity in light of controversial comments she made on the campaign trail that raised doubts about her patriotism.

"All of us are driven by a simple belief that the world as it is just won't do -- that we have an obligation to fight for the world as it should be," she said, closing the first night of the convention. Watch Sasha Obama review her mom's speech »

"That is the thread that connects our hearts. That is the thread that runs through my journey and Barack's journey and so many other improbable journeys that have brought us here tonight, where the current of history meets this new tide of hope.

"And you see, that is why I love this country," she said to a standing ovation.

Her husband praised his wife's speech when he addressed delegates in Denver via satellite Monday night after she finished speaking.

"You were unbelievable. You also look very cute," Obama, said. "Now you know why I asked her out so many times -- you want a persistent president."

The senator watched his wife's speech from Kansas City, Missouri, where he is scheduled to campaign Wednesday, spokeswoman Jen Psaki said.

He will give his main speech Thursday night, formally accepting the party's nomination at Invesco Field in front of an expected audience of 75,000. iReport.com: Share your reactions to DNC speeches

Michelle Obama was introduced at the convention by her brother, Craig Robinson, head basketball coach at Oregon State University.

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