Rep. Alexandria Ocasio-Cortez delivered one of the most coveted endorsements of the Democratic Party Saturday, when she made her support for Sen. Bernie Sanders official. It all happened at a massive rally in New York, which was the senator’s first since he suffered a heart attack earlier this month. In explaining her endorsement, Ocasio-Cortez detailed how Sanders played a pivotal role in her journey to becoming a lawmaker. “It wasn’t until I heard of a man by the name of Bernie Sanders that I began to question and assert and recognize my inherent value as a human being who deserves health care, housing, education, and a living wage,” Ocasio-Cortez said at the “Bernie’s Back” rally. Sanders’ campaign estimated the crowd at 26,000 people, which would make it the largest for any Democratic presidential candidate so far this year.

The New York lawmaker took pains to emphasize Sanders’ history in fighting for progressive causes. “When I was a child that relied on CHIP so that I could see a doctor, Bernie Sanders fought for a single-payer health care system,” she said. “When the federal government decided to discriminate and abandon my queer family and friends, Bernie Sanders was putting his career on the line for us.” She also said that her appreciation of Sanders has only grown ever since she arrived in Congress. “Every trick in the book, psychological and otherwise, is used to get us to abandon the working class,” she said.

Today I am endorsing Senator @BernieSanders for president.



In the end, we must come together to defeat Donald Trump. We should do so knowing he is a symptom of a larger problem - and our greatest hope is a multiracial, working class movement in the United States of America. pic.twitter.com/9fiTS7FTX9 — Alexandria Ocasio-Cortez (@AOC) October 19, 2019

Sanders returned the favor and praised Ocasio-Cortez. “I’ve been around politics a few years and it is hard to believe the degree to which in less than one year, this woman, the youngest woman ever elected to Congress, it is hard to believe the degree to which she has transformed politics in America,” Sanders said. The senator called the freshman lawmaker “an inspiration to millions of young people, not just here in New York, but across this country, who now understand the importance of political participation and standing up for justice.”

At one point in the rally, Sanders appeared to indirectly mention his health. “I am happy to report to you that I am more than ready, more ready than ever, to carry on with you the epic struggle that we face today,” he said. “I am more than ready to assume the office of president of the United States.”

Ocasio-Cortez’s endorsement is a major boost for a candidacy that while still at the top of the Democratic field appears to have stalled in the polls amid concern about Sanders’ health. Meanwhile, Sen. Elizabeth Warren has been able to take advantage of strong momentum to solidify her position as a frontrunner in the race alongside former Vice President Joe Biden. “There are few more notable endorsements on the Democratic side than AOC’s,” Rebecca Katz, a progressive consultant who advised Cynthia Nixon’s gubernatorial campaign in New York tells Politico. “This is a real shot in the arm for Bernie and helps energize the base.”