When the pesukim espouse the beauty of Yerushalayim, it is a metaphor for expressing the emotions of love between a Yid and his Creator. Since it is impossible to describe the depths of this love—for it is completely unconditional, and one who hasn’t tasted it cannot fathom it—Shir HaShirim describes it in metaphors. What was so beautiful about Yerushalayim? Was it the city’s external features?! Surely not.
The beauty of the city was in the pure hearts of the Yidden who were present there, and the love and closeness they felt to their Creator there!
When a Yid came to Yerushalayim, he became completely transformed. He understood that he was there to purify himself completely before the Ribbono shel Olam. “I want to offer a korban because I will thus become closer to the Ribbono shel Olam and no longer need to carry around my burdens.... It’s all worth it, no matter how difficult, and no matter how humiliating it may be to bring my korban chatas for my sins; it’s all worth it for the feeling of kirvas Elokim that I will experience.”
When Yidden were oleh to Yerushalayim, they encountered the Aibishter (see Chagigah 2a). The beauty of the city wasn’t in its exquisite alleyways, and the attribute of rabbati am (Eichah 1:1) wasn’t that there were masses of people there; rather it was due to the exalted type of people who could be found in Yerushalayim.
