Ramban explains that the Torah’s description of the Jewish people as Hashem’s “holy nation” and “treasured nation” is a reference to that which the Jewish soul is Hashem’s holy treasure that He stores for eternity after a person's passing. Since a person's soul, the primary element of his being, lives on after death, it is not fitting to mourn excessively over its departure from the body.
Elaborating on this theme, Tzror HaMor writes based on the Zohar (see Vayechi 245b): The Torah admonition against excessive mourning can be compared to a king who sent his son to a small rural village for an extended period to engage in study and to prepare himself for his future position of kingship. Eventually, the king summoned his son to return home and the friends that the son had made in the village mourned greatly over his departure. A wise man said to them: “Fools! Your friend is about to become king over the entire land, and you cry over his departure from this little village?” So too, Hashem sent the soul down to this lowly world to prepare himself for kingship by engaging in Torah and mitzvos. When Hashem summons him to return to Heaven and take up his position of kingship, his family and friends cry over his loss, sometimes too much. The wise Moshe addresses them, saying, “Don’t cry over him! He is ascending to the treasure room of souls in the loftiest heavens.” According to this interpretation of the verse, “You are Hashem’s children” means that the deceased is Hashem’s child and is now returning to his Father in Heaven.
The Sages cautioned against mourning excessively over the deceased, even in ways that do not include making cuts and bald spots (Moed Kattan 27b). Ramban writes that the Sages based their words of caution on the Torah’s prohibition against these two specific expressions of mourning. The Sages add that if a person extends the mourning period beyond that required by Torah law, Hashem says: “You do not care about the deceased more than I do!” In other words, excessive mourning implies that Hashem was cruel in removing the deceased from the world. In truth, Hashem’s love and compassion for each Jew is greater than that of a human father for his son, and all that He does is with the best possible intentions.
One might ask: If so, why does the Torah not prohibit mourning altogether? Abarbanel explains that it is natural for people to mourn over the loss of a relative or close friend, and it is also a fitting expression of honor for the deceased. However, in recognition of the fact that Hashem’s ways are just and good, the Torah sets limits for mourning.
When the Torah states that one may not make a bald spot "between your eyes," it means anywhere on the head (Makkos 20a). As to why the Torah specifies the region “between the eyes,” Rav Menachem HaBavli suggests that this hints at the head-tefillin, which are places “between the eyes” (Devarim 11:18). The Torah intimates that it is not fitting for the holy nation to deface their scalps by making a bald-spot, for indeed, that is the place where we ought to place the glorious crown of tefillin that represents Hashem’s kingship over the Jewish people.
We return to the Torah’s account of Avraham’s limited weeping over the sudden passing of his great and irreplaceable wife with whom he had forged a nation. The Vilna Gaon explains that Avraham realized that Sarah had accomplished all she was meant to accomplish in her lifetime. He therefore had no reason to cry over the departure of her soul, which was rising to its rightful, complete reward, so he cried only over the loss of her body (cited in Beis Avos, pg. 69). The words “Avraham came to eulogize Sarah and to cry over her” may thus be interpreted to mean that after eulogizing Sarah as the quintessential Eishes Chayil who had nothing left to accomplish in this world, he saw reason to cry only a limited amount. As the Torah goes on to relate, Avraham honored Sarah’s body to the greatest extent possible, expending much effort and a great sum of money to acquire for her a burial plot among the greatest people in history.
