| Quote #1
STEWARD: "Oh, sir, you know you are a greater man here than the king himself." (1.13)
This isn't just flattery. It's kind of true under the feudal system. Individual lords had more power in their own lands than kings did.
| Quote #2
JOAN: "We are all subject to the King of Heaven; and He gave us our countries and our languages, and meant us to keep to them." (1.152)
Joan was an early proponent of Nationalism, though she'd never call it that. This philosophy basically says the French people ought to be in France, English people ought to stay in England, and so on. Here we see her using her faith in God to justify her Nationalistic beliefs.
| Quote #3
THE ARCHBISHOP [sternly] "I speak in the Church's name. […]"
Excommunication was one of the main powers that the Church had over kings. If they were excommunicated, that meant they were going to hell. Even if the King didn't believe in it himself, the people wouldn't follow someone who was "damned."