On the 10th of Tevet of the year 3336 from Creation (425 BCE), the armies of the Babylonian emperor Nebuchadnezzar laid siege to Jerusalem. Thirty months later -- on Tammuz 17, 3338 -- the city walls were breached, and on 9 Av of that year, the Holy Temple was destroyed. The Jewish people were exiled to Babylonia for 70 years.
Link: Asarah B'Tevet
Tevet 10 is observed as a day of fasting, mourning and repentance, in remembrance of the siege of Jerusalem. We refrain from food and drink from dawn to nightfall, and add the Selichot and other special supplements to our prayers. (More recently, Tevet 10 was chosen to also serve as a "general kaddish day" for the victims of the Holocaust, many of whose day of martyrdom is unknown.)
Links:
Learn about Tevet 10
Essays and Stories on the Holocaust
If He loathes evil, then why does He allow it in His world? How can He breathe life into a world while all that is good and beautiful is ravaged by that which He hates?
It must be that His hatred of evil is not like the hatred of a mortal being for those who oppose him. Nothing can oppose Him, none of His creatures can cause Him harm. To Him, darkness is light and light is darkness, the wicked and the righteous are equal in their insignificance.
He rejects evil not for any reason, but only because He has chosen to reject these things, and that very rejection is what brings evil into being.
So too, He has chosen that those who vanquish evil will be called good. This, too, is a decision from His very essence, one that defines the very reality of things.
At the very core of reality lies the freedom of choice.