This evening, the ninth of Av ushers in the saddest day on the Jewish calendar. Terrible things have befallen our people, including the destruction of the first and second Temples. The Talmud explains:

Why was the First Temple destroyed? Because of the three elements, which existed in it: idolatry, immorality, and bloodshed. … However, why was the Second Temple destroyed, since at that time people were involved in study, mitzvot, and deeds of kindness? Because at that time there was senseless hatred among the people. This teaches that senseless hatred is as powerful an evil as idolatry, immorality, and bloodshed!
Talmud Yoma 96

The symbol of spiritual unity of the Jewish people was first destroyed because of terrible worst sins. We engaged in acts that denied the existence of the Divine in the world and in one another. The second time we denied the Divine in our fellow Jews. The sins hardly seem equivalent in severity.

When Jews or Jewish leaders bring break the law, we feel shame because others think less of Jews. The real shame we should feel is because people will think less of Torah and of following Gods teachings. For this reason, when Jews do things that attract negative attention, it is called a Chillul HaShem, a desecration of the Divine Name.

The Temples could exist only as long as we, the Jewish people, were faithful to our role as witnesses to the Divine. In the period of the Second Temple, Jews thought that by doing mitzvot, studying Torah and engaging in deeds of kindness, they were promoting God to the rest of the world, but they were mistaken. Disagreements among Jews were not just intense, but led to hatred. The brit (covenant) at Sinai was with every Jews. Only when we are whole as a people can we serve as witnesses of the greatness of God.

The Talmud teaches us that loving our fellow Jews and treating them, even when we disagree, with respect. In many cases, it appears to me, we have still not learned this lesson.