The Return of the King
How we cite our quotes:
"So may one counsel another," [Éowyn] said. "Yet I do not bid you flee from peril, but to ride to battle where your sword may win renown and victory. I would not see a thing that is high and excellent cast away needlessly."
"Nor would I," Aragorn said. "Therefore I say to you, lady: Stay! For you have no errand to the South."
"Neither have those others who go with thee. They go only because they would not be parted from thee—because they love thee." Then she turned and vanished into the night. (5.2.119-121)
When Éowyn tries to convince Aragorn not to go along the Paths of the Dead, she tells him point blank that the men who are accompanying him on this way are risking their lives not because they think it's a dandy plan, but because they love him. Éowyn's use of the word "love" has a double-meaning. When she's talking about Aragorn's companions, she means the friendship kind of love (at least, we assume). But she is also implicitly confessing her own feelings for Aragorn. She wants to go along, too, because she loves him, and not in a friendly sort of way.
Pippin pressed forward as they passed under the lamp beneath the gate-arch, and when he saw the pale face of Faramir he caught his breath. It was the face of one who has been assailed by a great fear or anguish, but has mastered it and now is quiet. […] Yet suddenly for Faramir his heart was strangely moved with a feeling that he had not known before. Here was one with an air of high nobility such as Aragorn at times revealed, less high perhaps, yet also less incalculable and remote: one of the Kings of Men born into a later time, but touched with the wisdom and sadness of the Elder Race. He knew now why Beregond spoke his name with love. (5.4.39)
Here's the thing about Faramir. He's high and mighty (like Aragorn), sure, but he's also "less incalculable and remote," and therefore much more likeable and approachable to folks like Pippin and Beregond. While Tolkien wants to describe the deeds of borderline superhuman figures like Aragorn or Gandalf, they are often so wise or so distant that it becomes difficult to identify with them personally (especially Gandalf the Perfect). In order to give something as epic as The Lord of the Rings an emotional anchor for the reader to sympathize with, he has to include some slightly less "remote" figures. While the hobbits fill that role for the most part, the occasional character like Faramir also helps us to remember that not every wise person is unemotional and inaccessible.
For there were servants of Denethor with swords and torches in their hands; but alone in the porch upon the topmost step stood Beregond, clad in the black and silver of the Guard; and he held the door against them. Two of them had already fallen to his sword, staining the hallows with their blood; and the others cursed him, calling him outlaw and traitor to his master.
Even as Gandalf and Pippin ran forward, they heard from within the house of the dead the voice of Denethor crying: "Haste, haste! Do as I have bidden! Slay me this renegade! Or must I do so myself!" Thereupon the door which Beregond held shut with his left hand was wrenched open, and there behind him stood the Lord of the City, tall and fell; a light like flame was in his eyes, and he held a drawn sword. (5.7.20-1)
We know that something is off with Denethor not just because he is dead set on burning himself and his son alive (though that is a pretty good indication that he is not a well man), but also because Denethor's actions in this scene remind us of the unjust orders Théoden gave while under the control of Saruman back in The Two Towers. Remember when he arrests Éomer for threatening Gríma Wormtongue in Book 3, Chapter 6? In the The Lord of the Rings, when a ruler starts turning on his own family and setting his soldiers against each other, it's a sure sign that he is possessed by some sort of Big Bad. Sauron's main weapon is corruption, and he loves taking good things and making them awful. For Denethor to decide to burn his son out of twisted love and guilt must have been a major coup for Sauron. The guy has actually managed to turn a father's love to murderous insanity. Nice job, Sauron.