Back when Elizabeth Warren was sworn into the Senate in 2013, it was then-Vice President Joe Biden that presided over the ceremony.

Eight years earlier, much like seven years later, both were fierce competitors on either side of a bill that made it more difficult to declare bankruptcy.

Biden led the charge for the bill and Warren, then a Harvard professor, was the face of the resistance. 

When he swore her into the Senate, Biden brought the battle up.

“You gave me hell! And you’re going to do a great job,” he said to the new Massachusetts senator.

Warren recalled the interaction in a video released April 15, 2020, as she endorsed Biden for president.

“That's the thing about Joe: He wants you in the fight with him. And when you're in the fight with Joe at your side, you know you have a partner who's committed to getting something good done for this country," said Warren.

In the video, she also spoke of Biden’s effort to understand and respect for those with different viewpoints than his own.

“He’s shown throughout this campaign that when you come up with new facts or a good argument, he’s not too afraid or too proud to be persuaded,” she said.

That’s something Biden is going to have to do more of if he wants to win over both Sanders and Warren’s supporters, which will be key to beating President Trump in November.

He started in March by agreeing with Warren’s bankruptcy proposal, which included repeals to some parts of the same bill they clashed with each other over 15 years ago

Warren held out on endorsing either Biden or Sanders when they both still sat within striking distance of the nomination. But with Biden growing an insurmountable lead, Sanders dropped out and then a week later, endorsed him.

She is the last of the once-massive Democratic field to do so.