How we cite our quotes: (Line)
Quote #1
A War Cabinet has been formed of five Members, representing, with the Opposition Liberals, the unity of the nation […] It was necessary that this should be done in one single day, on account of the extreme urgency and rigor of events. (4, 7)
Churchill explains why the change in leadership was necessary and how it's proceeding, so that Parliament can be reassured that there's a grownup in charge and they understand why he's doing what he's doing. He knew the first thing on his agenda had to be stabilizing the political situation.
Quote #2
Sir to form an Administration of this scale and complexity is a serious undertaking in itself, but it must be remembered that we are in the preliminary stage of one of the greatest battles in history, that we are in action at many other points in Norway and in Holland, that we have to be prepared in the Mediterranean, that the air battle is continuous and that many preparations have to be made here at home. (17)
Churchill's basically scaring his audience so they'll take the situation seriously, and focus on the war rather than their anger about losing Neville Chamberlain as prime minister.
Quote #3
In this crisis I hope I may be pardoned if I do not address the House at any length today. I hope that any of my friends and colleagues, or former colleagues, who are affected by the political reconstruction, will make allowance, all allowance, for any lack of ceremony with which it has been necessary to act. I would say to the House, as I said to those who have joined this government: "I have nothing to offer but blood, toil, tears, and sweat." (18-20)
Again, Churchill invokes the urgency of the war to excuse changes in parliamentary procedure. He knows people will be worried about the abruptness of the change. He follows with the reassurance that he'll give everything he has to win this thing.
Quote #4
You ask, what is our policy? I will say: It is to wage war, by sea, land and air, with all our might and with all the strength that God can give us; to wage war against a monstrous tyranny, never surpassed in the dark and lamentable catalogue of human crime. That is our policy. (23-25)
That description of the Axis powers would strike fear into pretty much anyone. The MPs listening were aware of the "monstrous tyranny," but for the past decade Parliament had been trying to appease them.
Quote #5
[…]without victory, there is no survival. Let that be realized; no survival for the British Empire, no survival for all that the British Empire has stood for, no survival for the urge and impulse of the ages, that mankind will move forward towards its goal. (27-28)
This is a popular justification for war: to protect our way of life. Churchill's upping the ante here—the future of humanity is at stake. The speech was genius in pointing out the dangers facing civilization while projecting a reassuring confidence of victory.