Or HaChaim on Genesis 23:2/אור החיים על בראשית כ״ג:ב׳

1 ותמת שרה בקרית ארבע. Sarah died at Kiryat Arba. We must not misunderstand that Kiryat Arba was the cause of her death. The reason the town was mentioned and was so named is to tell us that it was built on the four basic elements. Death normally implies a departure from, or disintegration of, the four basic elements that a body is composed of. When the Torah adds that "Kiryat Arba" is also known as חברון, this is an allusion to the word חבור, something that is joined together. The message is that when the righteous "die," this is not to be viewed as a process of disintegration. The righteous are still called "alive" even when they have ceased to function in regular bodies on this earth. The story in Shabbat 152 about how the grave of Rabbi Achai bar Yoshiah was disturbed by diggers on a property of Rav Nachman and how Rabbi Achai reacted illustrates this concept. What all this means is that while the righteous are alive in this world, the four basic material elements that every human being is composed of become transformed into something spiritual and attach themselves to their souls by means of the good deeds that such persons perform during their sojourn on earth. Maimonides illustrates this somewhat in the fourth chapter of Hilchot Yesodey Torah where he describes that one element is capable of becoming transformed into another element which was similar to it, i.e. earth can be transformed into water. When man cleaves to G'd all his elements become transformed into the element fire which forms the basis of the soul. Kabbalists are familiar with this.

2The Torah adds the (apparently superfluous words) "in the land of Canaan." This is an allusion to the fact that this present world is called ארץ כנען, a simile for the evil urge, Satan. This is so because the existence of Satan is the incentive for us to overcome him and to attain holiness and sanctity (Zohar 1,80).

3לספוד לשרה ולבכותה, to mourn Sarah and to weep for her. To mourn her departure from the world, and to weep for her on account of the personal loss he had sustained. One can also understand it in the reverse sense, i.e. he mourned the absence of her righteous presence, and he wept because she had tasted death and her sun had set (her benign influence on the people surrounding her).