The Little Prince is full of quotable passages. Here are a few.
What makes the desert beautiful is that it it hides a well somewhere.
This quotation is important because it articulates a central idea about beauty and truth. Even though one cannot know where the well is, the desert is nevertheless beautiful because we have faith that it contains the promise of life.
One sees clearly only with the heart. Anything essential is invisible to the eyes.
This quote—the fox's secret—represents a kind of thesis for the book. The ability to "see with the heart" and recognize the "invisible" suggests that empathy is more important than practical things.
The only things you learn are the things you tame.
The fox tells the Prince this as a way of explaining the need to spend time with others in order to get to know them. "Taming" is a key concept in the book; it implies a kind of mutual surrender, or agreement to care for each other.
Grown-ups never understand anything by themselves, and it is exhausting for children to have to provide explanations over and over.
This quotation is a comment on the pilot's difficulty in getting people to understand his drawings. It also expresses the central theme that imagination is more "real" than reality and that the process of growing up is, in part, the process of forgetting about the imagination.