Gemara: What is a "city of gold" (an ornament that it is forbidden to wear on Shabbat)? It is a golden ornament representing Yerushalayim, like the one Rabbi Akiva made for his wife.
Ein Ayah: There are two ever-opposing and competing powers – the power of limiting and that of exaggeration. Only when each has an impact is a good balance reached, which is built on the essence of the two coming together. We find this especially on the holy rest day of Shabbat, in which the spirit is expanded and is indulged.
It is women who are liable to lean too much in the direction of external adornment, which can cause many to sin and create havoc in families and nations. Girls have much more of an inclination toward adornment than men do. Just as the proper measure of adornment is precious and positive, so too its exaggeration is highly destructive to the spirit and the body. Regarding the holy day of Shabbat, the Rabbis were inspired to make limitations on adornments, albeit for ostensibly side issues. Specifically, as a result of showiness, one might remove jewelry and show such articles to others in the public domain, thereby desecrating Shabbat. Be it as it may, there is a restriction specifically on Shabbat, the holy day of indulging and rest, on the desire to show off in a manner that could strike roots that are too deep. Indeed, when fanciness is overdone, it can take the heart away from everything that is truthful and good, internal and eternal. Even when it starts out good and full of light, when it goes off course, it harms the center of life and sanctity in a terrible way. It can take that which is lofty and sacred and turn it into mundane, external, and petty.
The awakening of the heart of Jewish adornment is very pleasant when girls wear on their head a golden representation of Yerushalayim, the city of our internal strength. The legacy of good mothers represents that which is good in the nation, as "the Torah of your mother" refers to the Nation of Israel (Berachot 35b). The subjective understanding that creates a good feeling needs to be prepared by the sanctity of a mother, whose feelings come from the most basic feeling of her spirit, with the splendor which is unique to her. This is what Chazal meant when saying that Hashem braided Chava’s hair and presented her to Adam. It is at this point that the holy feeling of the nation as a whole has to find its place.
The best material for which to receive an attractive form is the fine feeling to host a divine soul, whose power comes from the highest intellect, which is connected to G-d’s Torah. This is best represented by a Jerusalem of gold ornament, which women who were very connected to their nation and Land wore. The center of their nation’s life was their adornment. However, this idea must not relate to a lowly physical object, without light, wisdom, or Torah-based internal grandeur. Rather it should be an outgrowth of the power of a pure feeling of connection to true knowledge of Hashem that is encapsulated in the Torah. When such a strong feeling toward the centrality of the nation comes from the right place, then it is a feeling of truth and justice that has eternal value.
The Jerusalem of gold we are speaking about was the type that Rabbi Akiva, the great "counter of the Torah’s letters," whose opinions are commonly assumed to be the correct ones, and whose soul departed when he completed Shema, made for his wife. This is a source from which national emotions are best. Even so, since these feelings are connected also to an external showiness, they need to be limited and kept in check. That is why, at least on Shabbat, one cannot wear such adornments, to show that physical adornments are not to threaten the prominence of the internal beauty of rest and sanctity of Shabbat.