1. Shavua tov. Today (Sunday) is the fast of the 17th of Tammuz. The fast began at dawn, around 4 AM in Israel, and ends with the appearance of stars (after 8 PM, in Israel). You can check the fasting times on Google, wherever you are in the world.
2. Why do we fast? On the 17th of Tammuz, the walls of Jerusalem were breached by Titus and the Roman army, about two thousand years ago. On the 9th of Av, the Temple was destroyed.
3. Therefore, this day opens the period called "Bein HaMetzarim" (or "the Three Weeks"), during which various mourning customs are observed for three weeks, until the 9th of Av.
4. Our sages tell us about four additional tragedies that occurred on exactly this date: On the 17th of Tammuz, Moshe descended from Mount Sinai, saw the Children of Israel sinning with the sin of the golden calf, and broke the tablets of the covenant. Additionally, the offering of the daily sacrifice in the Temple ceased, the wicked Apostomus burned the Torah scroll, and also placed an idol of foreign worship in the Temple.
5. On this day, when so many sacred things were undermined, our sages call upon us to engage in repair. To strengthen the foundation, the walls of our lives, the most important values and fundamentals. It is customary to increase on this day charity, prayer, Torah study, soul-searching, and other positive actions. The fast is not meant only to afflict the body, but to awaken the soul. To cause us to pause for a moment from routine, in order to examine it from the outside - and to repair.
