i decided to actually look up churchill's "their finest hour" speech and paste an excerpt here, but first, a little context for the speech, which was delivered on june 18 1940.
on sept 1 1939, germany invaded poland, prompting france and britain finally to declare war on germany. a mere nine months later, germany had conquered denmark, norway, belgium, and holland. on june 14 1940, the nazis marched into paris. czechoslovakia and poland were already under nazi control, italy was an axis power ruled by mussolini, and spain was a military dictatorship under franco. essentially all of europe was under fascist rule...except britain.
britain was utterly alone, facing the invincible military might of nazi germany. the united states? we wouldn't enter the war for another year-and-a-half, an eternity the way hitler was conquering nations. (besides, no one could know when, if ever, we would join the war.)
so that was the impossibly bleak situation britain was in when churchill, having become prime minister only a month ago, gave his speech which ended with these words:
What General Weygand called the Battle of France is over. I expect that the Battle of Britain is about to begin. Upon this battle depends the survival of Christian civilization. Upon it depends our own British life, and the long continuity of our institutions and our Empire. The whole fury and might of the enemy must very soon be turned on us.
Hitler knows that he will have to break us in this Island or lose the war. If we can stand up to him, all Europe may be free and the life of the world may move forward into broad, sunlit uplands. But if we fail, then the whole world, including the United States, including all that we have known and cared for, will sink into the abyss of a new Dark Age made more sinister, and perhaps more protracted, by the lights of perverted science.
Let us therefore brace ourselves to our duties, and so bear ourselves that, if the British Empire and its Commonwealth last for a thousand years, men will still say, 'This was their finest hour.'
full speech
here.