The powerful quote everyone's sharing after a speech at Ariana Grande's One Love concert.

It was an unforgettable day of healing, unity and star-studded performances, but 24 hours on from Ariana Grande’s One Love Manchester benefit concert one message is still being echoed around the world.

Shared onstage by Grande’s manager, Scooter Braun as the concert kicked off, he began, “I had the privilege of joining Ariana at the children’s hospital the other night and I’m proud to say there’s a TV set up right now and those kids are watching us. So please, say hello to all those kids.”

Braun, who also manages Justin Bieber, continued, "I promised one of those kids that I would deliver a message. His name is Adam, he's 15 years old, he lost his best friend Olivia that night. And after surgery, we met him. And just as I was about to leave the room he looked at me and said, 'Hey Scooter, make sure you tell them, don't go forward in anger. Love spreads."

Listen: Mamamia Out Loud discuss the importance of discussing the Manchester attack. Post continues... 

"Adam if you're watching, you're our hero tonight," Braun said as the 50,000 strong crowd cheered.

Within minutes, Adam's message was being shared across social media by thousands of people.

Adam's friend, Olivia Campbell, was one of 22 victims who lost their life in the Manchester terror attack on May 22.

"RIP my darling precious gorgeous girl Olivia Campbell," Olivia's mother, Charlotte Campbell, wrote to Facebook following her daughter's death. "Taken far far to [sic] soon. Go sing with the angels and keep smiling mummy loves you so much."

Following Braun's speech, Grande told the crowd that after meeting with Charlotte Campbell, she had changed the entire plan for the benefit concert.

“She told me to stop crying as Olivia wouldn't have wanted me to cry," Grande said. "And then she told me that Olivia would have wanted to hear the hits. So that means that we had a totally different show planned and we had a rehearsal yesterday where we changed everything."