Here have we war for war and blood for blood,
Controllment for controllment: so answer France.
Then take my king's defiance from my mouth,
The farthest limit of my embassy.
(5) Bear mine to him, and so depart in peace.
Be thou as lightning in the eyes of France,
For ere thou canst report, I will be there;
The thunder of my cannon shall be heard.
So, hence. Be thou the trumpet of our wrath
(10) And sullen presage of your own decay.--
An honorable conduct let him have.
I was worried when I started reading that there wouldn't be much in the way of beautiful imagery or metaphor in this play. I don't have a lot of experience with Shakespeare's history plays, but this passage has put my mind at ease.
Lines 1 & 2 are John's pronouncement. "You want to bring war to us? We will bring war to you!" These are very powerful statements. The phrase "blood for blood," is similar to the biblical eye for an eye. You shed out blood we will shed your blood.
Then in lines 5-11 we get this wonderful metaphor. King John dismisses the Chatillion (the emissary from France) and commands him to warn France. He compares this warning to the idea of thunder and lightning. In a storm, first you see the lightning and then a few moments later you hear the thunder, because of how sound travels. So, the Chatillion's warning will be the lightning and then John's cannons will be the thunder. And the closer they come to battle, the closer the lightning and the sound of the thunder will be. A great image, and I love the line: "For ere thou canst report, I will be there;" A very powerful line.
Since John seems to think a lot of himself, I am predicting that pride will be his downfall. A pretty good bet because that is the tragic flaw in almost all tragic heroes.