We are about the enter a period called Bain HaMetzarim, between the straits. It is a three-week span from the 17th of Tammuz to Tisha B’av, during which both of our holy Temples were destroyed.
The first Bais HaMikdash was destroyed by the Babylonians, and Chazal say that three sins led to its destruction: Idolatry, Bloodshed, and Immorality.
The second was destroyed because of Sinas Chinam, baseless hatred, name calling, and character assassination. While the first one was rebuilt after 70 years, the second one is still in ruins today, thousands of years later, proving that interpersonal hatred is worse than those three cardinal sins.
The Vilna Gaon explains that a person can be sucked into those sins, but they remain external to him. Hatred of others, though, comes from an internal flaw.
When the second Bais HaMikdash was destroyed, there was a group of ultra-nationalists who felt the Jews had to fight for themselves and defeat the Romans. These Beryonim burned the food supply and caused much suffering in their quest to be proven right, and this led to the destruction.
We must strengthen ourselves not militarily, but in our desire to serve Hashem and love our fellow Jew as He wants.
This is the only weapon we have in our arsenal to defeat our enemies and bring back the Bais HaMikdash.
