Lewis’ sentiments on the weightiness of being human come through beautifully in these two passages from Prince Caspian (chapters 13 and 15 respectively). Take heed all those who “come of the Lord Adam and the Lady Eve.”
“Very well, I will dictate,” said Peter. And while the Doctor spread out a parchment and opened his ink-horn and sharpened his pen, Peter leant back with half-closed eyes and recalled to his mind the language in which he had written such things long ago in Narnia’s golden age.
…it is our pleasure to adventure our royal person on behalf of our trusty and well-beloved Caspian in clean wager of battle to prove upon your Lordship’s body that the said Caspian is lawful King under us in Narnia both by our gift and by the laws of the Telmarines, and your Lordship twice guilty of treachery both in withholding the dominion of Narnia from the said Caspian and in the most abhominable, – don’t forget to spell it with an H, Doctor – bloody, and unnatural murder of your kindly lord and brother King Caspian Ninth of that name.
Here Lewis references a popular folk etymology of the word, in which “abhominable” was derived from the Latin ab homine “away from man” (beastly or inhumane). Our humanity gets another gentle prodding form Lewis in this passage from the end of the story:
“You, Sir Caspian,” said Aslan, “might have known that you could be no true King of Narnia unless, like the Kings of old, you were a son of Adam and came from the world of Adam’s sons. And so you are. Many years ago in that world, in a deep sea of that world which is called the South Sea, a shipload of pirates were driven by storm on an island…. Do you mark all this well, King Caspian?”
“I do indeed, Sir,” said Caspian. “I was wishing that I came of a more honourable lineage.”
“You come of the Lord Adam and the Lady Eve,” said Aslan. “And that is both honour enough to erect the head of the poorest beggar, and shame enough to bow the shoulders of the greatest emperor on earth. Be content.”