“Do not despair of our present difficulties but believe always in the promise and greatness of America,” McCain wrote before his death Saturday.

Charles Mostoller / Reuters

Republican Sen. John McCain authored a farewell letter before his death in which he warned Americans against political tribalism and said the country “will get through these challenging times.” In the letter, read Monday by longtime McCain aide and friend Rick Davis, McCain said he “lived and died a proud American.” “My fellow Americans, whom I have gratefully served for sixty years, and especially my fellow Arizonans, thank you for the privilege of serving you and for the rewarding life that service in uniform and in public office has allowed me to lead,” McCain’s letter began. “I have tried to serve our country honorably. I have made mistakes, but I hope my love for America will be weighed favorably against them.”

McCain expressed his vision of America as “the world’s greatest republic, a nation of ideals, not blood and soil.” The letter also appeared to contain a subtle rebuke of President Donald Trump. “We weaken our greatness when we confuse our patriotism with tribal rivalries that have sown resentment and hatred and violence in all the corners of the globe,” McCain wrote. “We weaken it when we hide behind walls, rather than tear them down, when we doubt the power of our ideals, rather than trust them to be the great force for change they have always been.” McCain, who died Saturday from an aggressive form of brain cancer, urged Americans to see their similarities, rather than focus on their differences. “We are three-hundred-and-twenty-five million opinionated, vociferous individuals,” he wrote. “We argue and compete and sometimes even vilify each other in our raucous public debates. But we have always had so much more in common with each other than in disagreement. If only we remember that and give each other the benefit of the presumption that we all love our country we will get through these challenging times. We will come through them stronger than before. We always do.”

BREAKING: A "final message" from the late John McCain is read by an aide.

McCain also said he was the “luckiest person on earth” and felt that way even as he faced death. “I owe that satisfaction to the love of my family. No man ever had a more loving wife or children he was prouder of than I am of mine,” McCain wrote. “And I owe it to America. To be connected to America’s causes — liberty, equal justice, respect for the dignity of all people — brings happiness more sublime than life’s fleeting pleasures. Our identities and sense of worth are not circumscribed but enlarged by serving good causes bigger than ourselves.” McCain, who represented Arizona in Congress for more than 30 years and ran unsuccessfully for president twice, recalled in his letter the day in 2008 he lost the presidency to Barack Obama. “Ten years ago, I had the privilege to concede defeat in the election for president,” McCain wrote. “I want to end my farewell to you with the heartfelt faith in Americans that I felt so powerfully that evening. I feel it powerfully still. “Do not despair of our present difficulties but believe always in the promise and greatness of America, because nothing is inevitable here. Americans never quit. We never surrender. We never hide from history. We make history. “Farewell, fellow Americans. God bless you, and God bless America.” Several memorials for McCain will be held throughout the week both in Arizona and Washington, DC. He will be buried Sunday in Annapolis, Maryland, where McCain attended the US Naval Academy.