Tisha B’Av is best known as the culmination of the National Mourning Period over the destruction of the First and Second Bais Hamikdash.
In truth the events of Tisha B’Av began much earlier when the Jews had left Egypt and were in the desert. They sent scouts ahead to the Land of Israel, who came back with a negative and discouraging report. The reaction was one of despair and lack of faith, and Hashem decreed that that generation would not be allowed to enter the Land of Israel. This happened on the night of Tisha B’Av, and at that point it was established to be a day of calamity for the Jewish People.
As mentioned, on that day both the First and Second Temples were destroyed. Additionally on the 9th of Av Beitar was destroyed, which effectively ended the Bar Kochba rebellion, resulting in the deaths of tens of thousands of men, women and children.
After the Bar Kochba revolt the Romans returned to Jerusalem and on Tisha B’Av they plowed the Temple Mount.
Throughout Jewish History Tisha B’Av has been designated as a day that is ripe for calamities. Events linked to various expulsions and crusades occurred on Tisha B’av, as is documented by Rabbi Becher here.
Although Yom Kippur is a joyous time and Tisha B’Av a mournful one, the five items that are prohibited on Yom Kippur are prohibited on the 9th of Av as well. (See here for a wonderful treatment of this).
The Shulchan Aruch states that one may not wash on Tisha B’Av, even to immerse one’s finger in water is forbidden (OC 554:7).
However this is limited to washing which would be considered ‘enjoyable’ as opposed to utilitarian. Therefore in cases of necessity the Halacha is lenient. Therefore, If one has to pass through water to visit their Rebbe or to rescue their assets they may, but they may not return through the water. Someone who is preparing food may rinse the food if necessary even though their hands will be washed as well.
Likewise, one should wash their hands upon arising and after using the restroom, but should be careful to only wash up to the major knuckles.
If one has actual dirt on their skin they may wash that area as well.
One may not put on creams or lotions on Tisha B’Av, as this is considered anointing. This prohibition extends to makeup and cosmetics as well, according to many poskim.
Deodorant is considered to be removal of dirt and is therefore permitted, however some halachic authorities write that one should not apply deodorant either, because it would be included in the prohibition of washing.
According to Halacha only a leather shoe is considered a shoe. Therefore, one may wear footgear made out of other materials, because they are not considered shoes.
There are those who are stringent, and say that nothing comfortable should be worn. There was some controversy several years ago when it was announced the leading Halachic authorities said one should not wear Crocs on Tisha B’Av. The truth is, they were not on a vendetta against weird looking rubber footwear, rather they were concerned about the opinions quoted by the Mishna Berura that discourage wearing anything comfortable on one’s feet. This would obviously include tennis shoes, canvas shoes, or fuzzy bedroom slippers as well. Although this is not Halacha or common practice, it’s good to be aware of the valid halachic opinion that one should refrain from wearing anything comfortable on their feet.
A shoe which has some leather in it is permitted if the leather is not supportive and is merely decorative. (Rav Moshe Feinstein quoted in Moadei Yeshurun).
According to some all practices of Harchakos should be observed, just as when a woman is a Nidda. Others are of the opinion that only the Torah mandated Harchakos are in effect. Some differentiate between the day and the night.
Eating and Drinking
Even those who wouldn’t fast on the minor fasts, such as a pregnant or nursing woman, should fast on Tisha B’Av. It goes without saying that if there is a medical need then one should consult with their doctor and Rabbi.
Additionally, since Tisha B’Av is a mournful time there are additional items which were enacted from a mournful perspective (See Chidushei Maran Riz Halevi on Hilchos Taanios for a full treatment of the dual aspect of Tisha B’Av).
Abstaining from Studying Torah
Torah Study brings joy and is therefore forbidden. There are specific sections one may study, particularly those that speak of the destruction of the Temple, Eichah and the sections of the Talmud that discuss mourning. When studying those sections he should not delve deeply in a way that will bring him joy.
One may say all the parts of prayer that he says on a daily basis, even if they are technically Torah study.
There are differing opinions on reciting Tehillim after midday. Before midday according to all opinion one should not say Psalms.
One may learn Mussar works only to the extent that they are used as an inspirational tool to introspect. (Rav Elyashiv Zt”l).
We refrain from greeting others be it verbally or by nodding ones head or bowing. If one is greeted they should reply to the extent that the other person won’t be slighted.
Sit On the Floor
One should sit on the floor until midday, or on a low stool that is lower than 3 tefachim (9-12 inches).
Additionally make an effort not to distract oneself from the mourning, thus not to engage in idle chatter.
Therefore one is to abstain from work and business related matters until at least midday and preferably the entire day.
Other Laws and Customs
1)Some don’t sleep on a bed, others replace their pillow with a stone, and one should make an effort to make their bed at least a little less comfortable.
2)One shouldn’t dress particularly nicely
3)One should refrain from smelling pleasant smelling spices, and smoking is not allowed in most circumstances.
4)Men do not wear Tallis and Tefillin at Shachris. This is because Tefillin is called פאר , our glory, and on Tisha B’Av our glory was taken from us
Other Tisha B’Av customs:
Cleaning the House
Many have the custom to clean the house and wash the floor after midday, so as to prepare for the coming of Moshiach, and to signify that even in the depths of our despair we do not give up hope. According to tradition Moshiach is born on Tisha B’Av.
One Should not clean the house, or even make the beds, until midday.
There is a widespread custom to visit the cemetery on Tisha B’Av. There is an old Jerusalem custom to gaze at the walls of Jerusalem to remind themselves of their unfinished state.
All who mourn Jerusalem will merit seeing in its rebuilding. (Taanis 30b)