What is the significance of Babi's words--"One could count the moons that shimmer on her roofs, or the thousand splendid suns that hide behind walls"?

These are the words that Laila turns to and remembers about goodbyes. They are the words of her father, as he said goodbye to Kabul. She doesn't understand their meaning when she first hears them, but she later comes to understand them as she returns to Kabul at the end of the story. Babi's recitation is a reminder of the Kabul that once was, and it is also a testament to Babi's belief in cultural heritage and education.... holding onto one's traditions.