At the Congressional Black Caucus Foundation gala on Saturday, President Barack Obama discussed higher education costs. (AP)

A combative President Obama reiterated Saturday night that he refuses to negotiate with Congress over funding for his signature health-care law and warned that Republican lawmakers are threatening to plunge the nation back into a painful recession.

In a fiery speech at the Congressional Black Caucus Foundation gala, Obama also renewed his push for sweeping new restrictions on firearms purchases. The president cited the recent rash of deadly shootings in his home town of Chicago, as well as Monday’s rampage at Washington’s Navy Yard, and exhorted lawmakers, “We’ve got to get back up and go back at it.”

Obama continued to blast House Republicans, charging that their “top agenda” was depriving millions of Americans of health-care coverage. On Friday, the House passed a plan that would avert a government shutdown and keep the government operating through mid-December but would also strip funding for the Affordable Care Act, known as Obamacare.

“It is not going to happen,” Obama said of the defunding measure. “We have come too far. We’ve overcome far darker threats than those.”

Obama also repeated his pledge not to negotiate over raising the government’s debt ceiling, saying America is obligated to pay its bills. Of House Republicans, he said, “it’s time for these folks to stop governing by crisis.”

At the Congressional Black Caucus Foundation gala on Saturday, President Barack Obama discussed the Affordable Care Act and the looming threat of a government shutdown. (AP)

Obama’s speech came at the CBC Foundation’s annual awards dinner, which paid tribute to the March on Washington that was led 50 years ago by the Rev. Martin Luther King Jr. Obama invoked King’s legacy and said that, five years into his presidency, “I am still fired up because I still see the work that needs to be done.”

Obama lamented that the unemployment rate for black Americans remains twice the rate for white Americans. He said he wants to improve the nation’s schools and increase the minimum wage, so that no working adult has to raise a child in poverty.

“We’ve got to pick up the torch of economic justice,” Obama said.

Obama spoke for the first time about the recent shootings in Chicago. He noted Saturday that just two days earlier, 13 people were shot during a pickup basketball game, including a 3-year-old girl. He linked the tragedy to the Navy Yard rampage — which Obama will address at a memorial service on Sunday — as well as mass shootings in Newtown, Conn., Aurora, Colo., and Tucson.

Across the country, people are being killed by gun violence every day, Obama said, “without headlines sometimes or public outcry.” Referring to his so far unsuccessful push for gun-control legislation, Obama continued, “We fought a good fight earlier this year, but we came up short, and that means we’ve got to get back up and go back at it.”