Former U.S. President Barack Obama delivered a blistering account of his successor's first four years in office on Wednesday in Philadelphia, arguing that President Donald Trump has proved he is "incapable of taking the job seriously" and has shown no interest in "helping anybody but himself and his friends."

The event is Obama's first stump speech for his former vice president, a welcome sight to Democrats who see the former president as Joe Biden's most potent character witness and a key factor in encouraging Black men, Latinos and younger voters to turn out and vote.

Obama's speech represented his most direct attacks on Trump to date, with the former Democratic leader leveling both substantive critiques -- like questioning Trump's tax policy and handling of the coronavirus pandemic -- and personal barbs, jabbing at shrinking ratings for the President's speeches and town halls.

The remarks drilled down on years of Democratic concerns about the President, with Obama arguing Trump's presidency has not only changed the way other countries view the United States but remade the way Americans feel about politics.

"I never thought Donald Trump would embrace my vision or continue my polices, but I did hope for the sake of the country, that he might show some interest in taking the job seriously," Obama said. "But it hasn't happened. He hasn't showed any interest in doing the work or helping anybody but himself and his friends."

The former President directly attacked Trump's handling of the coronavirus, the issue that is dominating the 2020 campaign.

Henoted that Trump recently said that there is "not much" he would change about the US response to the pandemic that has killed over 220,000 people in the United States.

"Really?" Obama asked. "Not much? Nothing you can think of that could have helped some people keep their loved ones alive?"

Standing in front of Lincoln Financial Field for the drive-in rally, Obama said a competent response to the coronavirus would have meant Philadelphia Eagles fans "would be tailgating here at The Link, instead of watching a speech from your cars."

Obama's remarks will undoubtedly anger Trump, who has continued to attack his predecessor even four years removed from his last day in office.

After Obama suggested Trump uses the presidency to boost his own profile, he added, "Even then, his TV ratings are down. So you know that upsets him."

And when he noted that Trump inherited a booming economy from him, Obama added, but "just like everything else he inherited, he messed it up."

The speech also showed Obama is closely watching the day-to-day news about Trump, including a Monday report that the President maintains a Chinese bank account.

"How is that possible? A secret Chinese bank account," Obama asked.

Then he reflected on the way that conservative media and Trump treated him during his time in office.

"Listen, can you imagine if I had had a secret Chinese bank account when I was running for reelection?" Obama asked. "You think Fox News might have been a little concerned about that? They would have called me Beijing Barry."

Obama also touted Biden and his running mate, California Sen. Kamala Harris, throughout the speech, saying that while he didn't know Biden well when they both served in the Senate, he "came to admire Joe as a man who has learned early on to treat everyone that he meets with dignity and respect."

Obama said Biden would "never call the men and women of our military suckers and losers," citing a bombshell report on Trump from The Atlantic. He said Trump has "emboldened" racists. Obama also incredulously recounted instances of Trump retweeting conspiracy theories, indirectly mentioning the false QAnon group that says there is a "secret cabal running the world."

"It just won't be so exhausting," Obama said of a Biden administration, adding voters are "not going to have to think about the crazy things ... and that is worth a lot."

This is a breaking story and will be updated.