(CNN) Former Vice President Joe Biden sought to rally House Democrats on Wednesday by forcefully attacking President Donald Trump while urging his own party to stay united.

"The President is looking out for himself only. The Republican Party seems to only be looking out for the President," Biden said in an auditorium at the Capitol, delivering the keynote address at a Democratic retreat. "And so it's our job to remind the American people that we're looking out for them."

Focusing much of his half-hour-long remarks on Trump, Biden hit the President as a narcissistic, divisive force that threatens the "moral fabric" of America.

"Who in God's name would have thought we would be here at this moment with this President? We have a President who is consumed by his political survival," he said. "Everything is run through the filter of how it affects Donald Trump in Donald Trump's mind."

With "his closed and clannish nationalism" and "ugly and phony populism," Biden argued, Trump was shredding "decency" and "honesty."

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