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
Intellect is inadequate because not all things can be explained. Intellect needs faith.
Faith is impotent because it remains forever obscure. Faith needs intellect.
But they are opposites, as contradictory as yes and no:
Faith accepts; Intellect questions.
Faith surrenders; Intellect struggles.
Miraculously, there is a power that can join them in harmony, and it is called wisdom.
Wisdom is the capacity to see the truth as it is
and the quietness to allow it entry without compromise.