"A friend's word is the truth itself. If I think of touching, even with one finger, the son of Anne of Austria, the true King of this realm of France; if I have not the firm intention of prostrating myself before his throne; if, according to my wishes, to-morrow here at Vaux will not be the most glorious day my King ever enjoyed,- may Heaven's lightning blast me where I stand!" (14.104)
Aramis is lying through his teeth. This is not honorable at all.
"Sire, you would be dishonoring yourself if you were to give such an order."
"Dishonor myself?" murmured the King, turning pale with anger. "In truth, Mademoiselle, you put a strange eagerness into what you say." (15.33 – 15.34)
Invoking honor is a sure-fire way to win an argument.
"Monseigneur," replied the Gascon, touched by his eloquent and noble tone of grief, "will you- I ask it as a favor- pledge me your word as a man of honor that you will not leave this room?" (19.111)
The word of a man of honor can always be trusted.
"He was my guest; he was my King!"
Aramis rose, his eyes literally bloodshot, his mouth trembling convulsively. "Have I a man out of his senses to deal with?" he said.
"You have an honorable man to deal with." (21.203 – 21.205)
The rules of hospitality dictate that the host is responsible for the guests. Aramis has deeply dishonored Fouquet, and that's the primary reason Fouquet sides with the King.
"If you had killed me, d'Artagnan, I should have had the good fortune to die for the royal house of France; and it would be an honor to die by your hand,- you, its noblest and most loyal defender." (32.5)
What does an "honorable" death look like? This passage indicates that the type of man who kills you must be of high quality in order for you to die honorably.
"I am dishonored!" thought the Musketeer; "I am a miserable wretch!" Then he cried, "For pity's sake, M. Fouquet, throw me one of your pistols that I may blow out my brains!" But Fouquet rode on. (40.40)
According to the Musketeers' code, if you cannot fulfill your duty, the honorable thing to do is kill yourself. D'Artagnan manifests that behavior here.
D'Artagnan raised himself up, looking round with a wandering eye. He saw Fouquet on his knees, with his wet hat in his hand, smiling upon him with ineffable sweetness. "You are not gone, then?" cried he. (40.47)
A less honorable man would have run away. This is an indication of the type of hold the concept of "honor" has over these men.
"We shall gain the consciousness, Monsieur, of not having made eighty of the King's Guards retire before two rebels. If I listened to your advice, Monsieur, I should be a dishonored man; and by dishonoring myself I should dishonor the army. Forward, men!" (48.122)
Even if the captain would have liked to stand down, honor dictates that eighty men cannot retreat before two.
"Captain," said Biscarrat, "I beg to be allowed to march at the head of the first platoon."
"So be it," replied the captain; "you have all the honor of it. That is a present I make you." (48.124 – 48.125)
It is an honor to be the first to die in battle.
"I shall go as I am, Captain," said Biscarrat, "for I do not go to kill, I go to be killed."
And placing himself at the head of the first platoon with his head uncovered and his arms crossed, "March, gentlemen!" said he. (48.128)
This proves Biscarrat is a truly honorable man, for he compensates for the lives of his companion by being among the first to die.