Our Chachamim z"l tell us that the First Bet Hamikdash was destroyed because of three sins: Avodah Zarah/Idolatry, Shefichat Damim/Murder, and Arayot/Adultery. The second Temple of only one sin - Sinat Chinam - Baseless Hatred.
Each of the sins are bad in their own right, but it took three sins to bring down the First Temple and only one the Second. Why? Why only one, what is so destructive and bad about it?
Let's dive into Sinat Chinam cause I believe the reasons for the destruction of the First Temple are pretty self explanatory.
So what is Sinat Chinam? It is Baseless Hatred or simply Hate that is coming from a place of evil. It's a wish to see another's demise or failure and when you in that hating mode you observe and translate anything that person does to negative with no benefit of a doubt.
When you hate you always pursue the harm of another. You speak of him in harmful way, you make up stories so you get more people on your side to believe the lies, so he can have enemies. You speak and spread lashon hara - an evil speech, because you want others to see him in a bad way. You may say things to his spouse, so the family will have no peace and eventually falls apart. You accuse him and his children, so it should effect their shidduchim/marriage prospects. You make sure his reputation is ruined in his community and places of business. You make sure your family and people around him show him a cold shoulder so he feels unwanted and unbelonged.
All of this is done stealthily where few people involved in the community or many across many communities. In our times, all of the above can be accomplished with just few clicks of the computer or the phone.
Because of this ugly behavior, of the few or the many, Hashem has destroyed the Second Temple. So if the Temple is destroyed and it may seem like nothing is at stake today, what do we have to lose this time around?
Chachamim tell us, that when a new family is born, the chatan and kallah are on their way to build something enormously holy - their Own Bet Hamikdash, where each room of their house resembles the original Temple. The bedroom is like the Holy of Holies, the living room table is like a Mizbeach where we cater the guests and consume our earthly sacrifices. Kitchen is where it's all prepared to the strict laws of kashrut.
Our houses and shules are small Batey haMikdashim. This is where Shechina rests, this is where the mitzvot are done and kedusha is kept.
Hashem wants peace and unity between people in the community or between communities, where people help each other, happy for each other, where they see good in each other with no jealousy and hate towards each other. Where they want others to have better houses, cars, vacations, respect and accessories. This is what Hashem expects from his people.
Second Temple was destroyed because of Hate, the most ugliest trait that consumes many communities and people no matter their religious backgrounds. The solution to it is Achavat Chinam - Baseless Love. Otherwise our small Batey haMikdashim are at stake.
The Sages taught, "Any generation in which the Temple is not built, it is as if it had been destroyed in their times" (Yerushalmi, Yoma 1a).
Our job is to change for the better, to do good to others, more of baseless love and no hate and animosity towards others - be it in their own community or outside of it, better ourselves in our servitude to Hashem and earn the merit to see Moshiach and the Third Beit Hamikdash rebuilt in our days. Amen.