Arizona Sen. John McCain tweeted Thursday morning that he greatly appreciated "the outpouring of support" following the announcement he was diagnosed with a glioblastoma brain tumor.

He added that "unfortunately for my sparring partners in Congress, I'll be back soon, so stand-by!"

Everyone from Pres. Donald Trump and Pres. Barack Obama to the Arizona Cardinals and wide receiver Larry Fitzgerald have sent well wishes to the senior Republican senator from Arizona.

One theme was consistent across many of the tweets -- that McCain is a tough and worthy adversary in the battle ahead.

Obama told McCain "to give it hell."

The Cardinals released a statement saying "There is not a person who has embodied toughness and courage throughout his life like John McCain."

Fitzgerald said "they don't come any tougher.

Arizona Diamondbacks President and CEO Derrick Hall said there was no bigger fan of the team and McCain would "win another battle."

The Phoenix Suns said the team was sending its best to "one of the toughest there is."

The Arizona Coyotes said he was a hero and part of the family.

McCain's counterpart, Sen. Jeff Flake, tweeted that he spoke to McCain on Wednesday night. "Tough diagnosis, even tougher man."

Arizona's Gov. Doug Ducey said John McCain was "undoubtedly the toughest man in the US Senate" and has served the country "like few ever will."

His daughter, Megan McCain, shared an emotional note about her father Wednesday, saying that "he is the toughest person I know."