Now the trumpet summons us again — not as a call to bear arms, though arms we need — not as a call to battle, though embattled we are — but a call to bear the burden of a long twilight struggle, year in and year out, “rejoicing in hope, patient in tribulation” — a struggle against the common enemies of man: tyranny, poverty, disease and war itself.

John F. Kennedy (1917–1963) American politician, author, journalist, US President (1961–63)
Speech (1961-01-20), Inaugural Address, Washington, D.C.
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(Source (Video)). The quotation is from the Bible, Romans 12:12.

Portions of this are one of the seven quotations by JFK at his grave site in Arlington National Ceremony.