On Monday, the NBA world lost a giant with the death of Dikembe Mutombo at the age of 58. Throughout the day, members of the basketball world paid tribute to the Hall of Famer and humanitarian, honoring his legacy both on and off the court.

The NBA announced the news Monday morning with a statement from commissioner Adam Silver about his personal relationship with Mutombo, who became a global ambassador for the NBA.

Mutombo’s son, Ryan, wrote a heartfelt message on Instagram, calling his father his hero and “the purest heart I have ever known.”

The Atlanta Hawks, who retired Mutombo’s No. 55 jersey in 2015, mourned his passing. Principal owner Tony Ressler called Mutombo “a proud and honorable man, who lived up to the definition of a word that became synonymous with his name: humanitarian.”

The Houston Rockets, with whom Mutombo ended his 19-year career, paid tribute to the late NBA great on social media. In a statement, Rockets owner Tilman Fertitta wrote: “Dikembe was loved by the entire NBA community and his tireless humanitarian efforts left an indelible mark on our league.”

With news of Mutombo’s passing coming on the same day as NBA media day, many NBA players spoke about Mutombo’s legacy during their press conferences.

Philadelphia 76ers star Joel Embiid spoke about Mutombo’s impact both on and off the court. Embiid, a native of Cameroon, said the Congolese player was a role model.

“It’s a sad day, especially for us Africans, and actually for the whole world, because apart from what is accomplished on the basketball court, I think he was even better off the court,” Embiid said, via Yahoo’s Vincent Goodwill Sports. “He’s one of the guys I look up to when it comes to having an impact. He’s done a lot of great things for a lot of people.”

Daryl Morey, president of basketball operations for the Philadelphia 76ers, also spoke about Mutombo Monday morning, saying the NBA great became Morey’s mentor while they were both in Houston. The two overlapped in 2007, when Morey began his career as general manager, until Mutombo’s retirement in 2009.

“There aren’t many guys like him,” Morey said, via Mike Vorkunov of The Athletic. “Just a great person.”

Toronto Raptors president Masai Ujiri also spoke about Mutombo during his press conference and was very emotional when talking about his friend’s passing.

“It’s really hard to believe, and it’s hard for us to be without that guy,” Ujiri said, via Lindsay Dunn of CityNews Toronto. “He has no idea what Dikembe Mutombo meant to me.”

Chris Paul spoke about Mutombo at the San Antonio Spurs media day, saying he met Mutombo when the two played at the 2015 NBA Africa Game in Johannesburg, South Africa.

“Dikembe and what he has done for the league, his personality… he is a legend and he will be missed,” Paul said.

NBA Hall of Famer Pau Gasol wrote about Mutombo on social media, talking about Mutombo’s prowess on the court, and his kindness off it.

Cindy McCain, widow of Senator John McCain, wrote about Mutombo’s humanitarian efforts. Through its Mutombo Foundation, the NBA has created major hospitals, improved infrastructure, supported the growth of basketball and much more in its native Congo.

“My dear friend Dikembe Mutombo passed away today from brain cancer. I knew him as a true humanist. Here we are together in a refugee camp trying to help people who couldn’t help themselves. I will love him and miss him terribly,” said McCain. in a statement about X.

The Special Olympics paid tribute to Mutombo, who was a Global Ambassador and board member of the organization. In a statement about X, the Special Olympics called Mutombo a “champion of inclusivity” and “a colossus on and off the basketball court.”

Serge Ibaka, a former NBA player currently playing in Europe, thanked Mutombo for his pioneering efforts as an African player in the league. Born in the Republic of Congo, Ibaka played in the NBA for almost fifteen years.