Retired neurosurgeon Ben Carson has officially endorsed Donald Trump for president, arguing that the billionaire businessman is the "only candidate the GOP has that can defeat Hillary Clinton in 2016 and return America to that shining city on a hill."

At a press conference in Palm Beach, Florida on Friday, Carson described "two Donald Trumps" - the bombastic individual seen on stage, and the private, "very cerebral" person who "considers things carefully."

Carson cautioned that it is "extremely dangerous" when political parties attempt to "thwart the will of the people," and encouraged politicians to "strengthen the nation," rather than create divisions within the GOP. 

In introducing Carson on Friday morning, Trump described his formal rival as a "special, special person - special man," and a "friend" who is respected by everyone. He said his endorsement "adds total credence to what I'm trying to do." 

In a statement shared on his personal Facebook page on Friday morning, Carson, who dropped out of the presidential race earlier this month, also emphasized that the United States is "at a crossroads and in the midst of a moral crisis."

"We must be careful not to continue our current path, which is littered with uncertainty at best and ruination at worst. We can make changes to our system and that change starts now with, 'We the People,'" the 64-year-old wrote, underscoring the importance of not allowing disagreements to "divide us as a party or as a country."

"It is with that in mind that I endorse Donald Trump for President," Carson continued. "I have known Donald for many years. He is a successful businessman who has built a recognizable global brand that no one can question. His experience as a businessman is exactly what we need to move our economic engine in the right direction and empower those who have been left out of the American dream for far too long."

He added, "With our support, I am sure that we can help restore America's values and faith."

Carson also clarified that past feuds with Trump are "forgiven": "We have moved beyond the past, as the future is now."

He concluded his message by urging Republicans to unite in supporting and rallying around the "only candidate the GOP has that can defeat Hillary Clinton in 2016 and return America to that shining city on a hill."

Carson's endorsement of Trump will likely provide the GOP frontrunner with a potentially significant boost among Evangelical voters, as he developed a strong conservative and Evangelical following in 2013 after he advocated a flat tax, private medical savings accounts and other conservative policies at a National Prayer Breakfast speech that was attended by President Barack Obama.

The former neurosurgeon frequently cited his faith as a driving force behind his campaign, and when asked in September to name the biggest difference between himself and Trump, Carson stated, "Probably the biggest [difference] -- I've realized where my success has come from, and I don't in anyway deny my faith in God," he said to reporters in Anaheim, California.

Carson had briefly overtaken Trump in the polls earlier in the 2016 campaign, but suspended his campaign on March 4 after failing to win a single primary contest.