SPRINGFIELD - Amid deep national economic uncertainty, President Barack Obama paused for a moment Thursday to pay homage to Abraham Lincoln. | VIDEO: Obama's speech | ISU honors Lincoln | Big day for David Davis Mansion | VIDEO: Central Illinois recites Gettysburg Address | Obama and Lincoln

Back in Springfield for the 200th birthday celebration of the nation's 16th president, the new president told a sold-out dinner crowd that Lincoln's leadership during tumultuous times serves as an inspiration and a reason for him becoming president.

"It is a humbling task, marking the bicentennial of our 16th president's birth, humbling for me in particular, because it's fair to say the presidency of this singular figure in so many ways made my own story possible," Obama said.

Obama's visit to the place from which Lincoln launched his presidency came after a day in which he continued trying to shore up support for an expensive economic stimulus plan aimed at pulling the nation out of a recession.

His visit to East Peoria earlier in the day was aimed at prodding Congress to move quickly through the final steps of approval for the legislation.

"We've got to get the job done," he told workers at a Caterpillar Inc. factory there.

While he faces the daunting task of trying to rebuild a broken economy, the Chicago Democrat said Lincoln understood the importance of keeping the nation from fracturing over the issue of slavery.

"He recognized that while each of us must do our part, work as hard as we can, and be as responsible as we can, although we are responsible for our own fates in the end, there are certain things we cannot do on our own," Obama said. "There are certain things we can only do together. There are certain things only a Union can do."

Obama, a former state and U.S. senator and the first African-American to be elected president, has leaned heavily on Lincoln's legacy during his political tenure.

When he launched his presidential campaign, he did it in Springfield, in front of the Old State Capitol, where Lincoln served.

He returned to the same place on a blistering hot day last summer to unveil his choice for running mate.

As he took the oath of office on the steps of the nation's Capitol last month, his hand rested on the same Bible Lincoln used in 1861.

In his speech, he invoked Lincoln in his call for the nation to get behind his plan.

"Only by coming together, all of us, in union, and expressing that sense of shared sacrifice and responsibility - for ourselves, yes, but also one another - can we do the work that must be done in this country," Obama said. "That is part of the definition of being American."

Obama arrived in Springfield aboard Air Force One about 6:15 p.m. Thursday. He was greeted by a contingent of National Guardsmen and paused briefly to shake some hands.

His only appearance in the city was at the Crowne Plaza hotel, where the Abraham Lincoln Association was holding its annual birthday dinner.

The dinner for more than 1,000 people had to be expanded to accommodate the president's visit. In addition to those in the main dining room, a separate room was added where attendees could watch his remarks on a video screen.

Despite a warm welcome and a festive atmosphere, several reminders of problems in Obama's home state were front and center.

Republican powerbroker William Cellini, who has been charged in an ongoing federal criminal probe of corruption in state government, attended the banquet with his wife, who is a member of the state's Lincoln bicentennial commission.

Obama sat at a head table with Gov. Pat Quinn, who ascended to the post after Obama's former colleagues in the state Senate removed Rod Blagojevich from office amid corruption allegations. Also sitting nearby was former Illinois first lady Lura Lynn Ryan, whose husband, George, is in a federal prison after his own corruption conviction.

Former Gov. Jim Edgar, who served as an emcee of the event, acknowledged the state has "taken its lumps" in recent months.

"Illinois politics is not perfect," Edgar said.

Following Obama's 16-minute speech, the president headed back to the airport and departed for Washington, D.C.

Obama had begun the day with a ceremony honoring Lincoln at the Rotunda of the U.S. Capitol. Expressing "a special gratitude" to the political giant who in many ways made his own story possible, Obama said Lincoln's desire for unity and not revenge after the Civil War is a lesson for today.

"We are far less divided than in Lincoln's day," but "we are once again debating the critical issues of our time," he said. "Let us remember that we are doing so as servants to the same flag, as representatives of the same people, and as stakeholders in a common future.

"That is the most fitting tribute we can pay and the most lasting monument we can build to that most remarkable of men, Abraham Lincoln."

The Associated Press contributed to this report.