“Let us praise heaven and have faith in the future: We shall see that not even the power of our enemies will weaken our determination to promote the ideals we are fighting for.”

1930s, Speech to the Democratic National Convention (1936)
Context: We do not see faith, hope, and charity as unattainable ideals, but we use them as stout supports of a nation fighting the fight for freedom in a modern civilization.
Faith — in the soundness of democracy in the midst of dictatorships.
Hope — renewed because we know so well the progress we have made.
Charity — in the true spirit of that grand old word. For charity literally translated from the original means love, the love that understands, that does not merely share the wealth of the giver, but in true sympathy and wisdom helps men to help themselves.

2000s, 2004, Speech at the Republican National Convention (2004)

addressing a meeting of delegates to the Continental Congress, assembled at Yorktown, Pennsylvania, September 1777 ; as quoted in The Life and Public Services of Samuel Adams, Volume 2, by William Vincent Wells; Little, Brown, and Company; Boston, 1865 ; pp. 492-493

Speech to Parliament (10 April 1593), quoted in Leah Marcus, Janel Mueller and Mary Rose (eds.), Elizabeth I: Collected Works (The University of Chicago Press, 2002), p. 332.

Often attributed to Stalin, there is not a single source which show that Stalin said this at any given time. There is only one source outside the blogosphere which attributes the quote to Stalin, but does not provide any evidence for the attribution. That source is the book Quotations for Public Speakers : A Historical, Literary, and Political Anthology (2001), p. 121 by the former US senator Robert Torricelli.
Misattributed

1920s
Source: Nationalsozialismus oder Bolschewismus? (National Socialism or Bolshevism), open letter to “My Friends on the Left,” Nationalsozialistische Briefe (National Socialist Letters), (Oct. 15, 1925); Joseph Gobbles, Quoted in The Devil’s Disciples, Anthony Read, W. W. Norton & Company, 2005, p. 142

“On Tactics Against Japanese Imperialism” (December 27, 1935)

1860s, Cooper Union speech (1860)
Context: Neither let us be slandered from our duty by false accusations against us, nor frightened from it by menaces of destruction to the Government nor of dungeons to ourselves. Let us have faith that right makes might, and in that faith, let us, to the end, dare to do our duty as we understand it.
Context: Neither let us be slandered from our duty by false accusations against us, nor frightened from it by menaces of destruction to the Government, nor of dungeons to ourselves. Let us have faith that right makes might; and in that faith, let us, to the end, dare to do our duty, as we understand it.

1940s, Prayer on D-Day (1944)