On Saturday, Vermont senator and Democratic presidential candidate Bernie Sanders gave his first campaign rally since having a heart attack earlier this month. An estimated 26,000 people crowded into the venue in Queens, according to Politico, making it the single largest campaign event of the primary so far. "I am more than ready to take on the greed and corruption of the corporate elite and their apologists. And I am more ready than ever to create a government based on the principles of justice—economic justice, racial justice, social justice and environmental justice" he said, adding, "To put it bluntly, I am back."

Sanders needed a strong showing after having a heart attack on the campaign trail shortly before the most recent Democratic debate. The top three candidates in the primary—Sanders, Massachusetts senator Elizabeth Warren, and former vice president Joe Biden—are all in their seventies, and at 78 Sanders is the oldest candidate in the race. His stay in the hospital prompted many to ask, like a recent Los Angeles Times editorial, "How old is too old to be president?"

But he's back with a coveted endorsement: progressive darling and the youngest woman elected to the House of Representatives, Alexandria Ocasio-Cortez of New York. Ocasio-Cortez volunteered with the Sanders campaign in 2016, but she was reportedly torn between supporting him and Warren in 2020 until Sanders's heart attack. As someone close to her recently told Business Insider, "Her reaction was that this is ... when he needs an injection of energy in the campaign and she thought, 'If I have any capacity to do that, I should try.'"

Speaking to the crowd on Saturday, Ocasio-Cortez said that she's an even bigger admirer of Sanders after her experience in Congress:

"I can tell you the halls of Congress are no joke. It is no joke to stand up to corporate power and established interests. It is no joke. It's not just about standing up and saying these things, but behind closed doors your arm is twisted, the vice pressure of political pressure is put on you, and every trick in the book, psychological and otherwise, is use to get us to abandon the working class. And it has been in that experience over the last nine months that I have grown to appreciate the enormous, consistence, and nonstop advocacy of Senator Bernie Sanders."

This week Sanders also picked up the endorsement of Minnesota congresswoman Ilhan Omar, and Rashida Tlaib of Michigan is expected to endorse him this coming week.

NOTE: An earlier version of this article incorrectly stated that Bernie Sanders is 79 years old. He's 78. We regret the error.