so people won't be around their dead because of their love and have too much tzaar." This is similar to the Ramban (Devarim 14:1), who explains the reason it is forbidden for a person to cut himself or to make a למת קרחה, baldness in the head, due to mourning. He explains that the soul lives forever; it remains eternally under Hashem's care, so there is no reason to mourn excessively.
The Ramban writes, "Neshamos will exist eternally before Hashem... because you are a holy nation, the treasure of Hashem... and Hashem thinks how no soul should ever be detached from Him. Therefore, there is no reason for a person to cut himself or to make baldness over the dead, even if someone died young... And this is the source for Chazal (Moad Kotton 27) who forbade mourning excessively over a dead."
This lesson doesn't solely apply to when someone dies, chalilah. Other losses can occur in a person's life, other disappointments, but it is forbidden to mourn excessively over these matters. With the belief that everything is for the good, there is no reason for excessive tears. Hashem wants a person to rise from the ashes and be strong with joy. A person shouldn't say, "How can I be happy when I have this great tzaar?" The emunah that פעלו תמים הצור, that Hashem is leading us in the best way, לטב רחמנא דעביד וכל עביד, and everything Hashem does is for the good, will make it easier for him to accept the yesurim.
The four letters of Hashem's holy name can be rearranged and written in twelve combinations. Each month, another combination and order of Hashem's name shines. For example, for the month of Tamuz, the arrangement of the letters of Hashem's name is written backwards, like this: י"הוה. This comes from the final letters of the pasuk in megilas Esther (5:13) לִי שׁוֶֹה א ֵינֶנּוּ זֶה וְכָל , " But all this is worth nothing to me..." Haman said that he has wealth, family, and honor, but he has nothing at all because Mordechai doesn't bow down to him.
The Birkas Avraham quotes from mekubalim that the month of Tamuz fell into the hands of Eisav. Indeed, the attitude of Eisav and Haman is to complain that they have nothing. Even if they lack just one matter, they feel like they have nothing. In contrast, for Yaakov Avinu and his descendants, they have ז"תמו, which is roshei teivos for מלכנו זכרך ותרומם תפאר. We praise Hashem for all His kindness. We focus on what we have, and not on what we lack. We aren't like Haman who says לִי שׁוֶֹה א ֵינֶנּוּ זֶה וְכָל, and זֶה means something small. This is because Haman complains when he lacks even the smallest thing. In contrast, we, the descendants of Yaakov Avinu, say (Shemos 15:2) וְא ַנְוֵהוּ לִי-אֵ זֶה וַא ֲרֹמְמ ֶ נְהוּ א ָבִי א ֱלֹקֵי. It says זֶה in this pasuk, because even for the smallest matters, we praise and exult Hashem's name.
