Razan al-Najjar, 21, was shot dead by Israeli soldiers on the border between Israel and Gaza over the weekend.
A woman identified as Najjar's mother, Sabreen, spoke about her daughter as she clutched a blood-stained medical vest with a single hole in it.
Thousands attended her funeral, with observers saying the mosque was so full that people stood on the rooftops and streets around to pay their respects to her.
During the funeral, where her coffin was draped in the Palestinian flag, her father brandished her bloodstained white medical vest.
She has become an international symbol of the violence in Gaza, with thousands of tweets celebrating her work and life.
"She literally gave everything," her cousin Dalia al-Najjar told BuzzFeed News.
Dalia, 22, who spoke from Istanbul where she had received the news, said her aunt, Najjar's mother, always described her daughter as like a "butterfly."
"She was someone who spread love and positivity around her," she said. "She’d be jumping around, touching everyone, making everyone happy."
"After Ramadan, we have the Eid celebration, so she bought new clothes for all her siblings but one, and she said, 'I’ll do it next week.' But she couldn’t," Dalia said.
"She is a fighter for peace," Dalia said, describing how her cousin would log 10 hours out in the field evacuating and treating the wounded, even during Ramadan when many other first responders were struggling to cope. "Every day, with all her clothes covered in blood [she would come home], and her mother would tell her, 'Why would you do this to yourself?'
"Her message to the world is that without weapons we can do everything. She is a symbol for peace."
Dalia said her cousin was "a great person, a great person. I would love people to honor that and to learn what she has been doing and be like her. A kind, selfless person."