Once the month of Ab begins, “our happiness decreases”, because we are preparing ourselves, gradually and emotionally, for the 9th of Ab, the day of national mourning of the Jewish people. Thus, Jewish tradition indicates that we should avoid certain activities associated with joy or celebration, engagement parties or weddings are not allowed during these days, in addition to the other restrictions that are already in effect from the 17 of Tamuz. See here and here.
We will focus our attention now on other topics mentioned by the Shulchan Arukh: 1. MASA UMATAN, 2. NETIA, 3. UBINYAN SHEL SIMHA (buying, shopping; planting and building in a context of celebration ).
MASA UMATAN SHEL SIMCHA:
It is customary to refrain from buying new clothes, jewelry or other luxury items from Rosh Chodesh Ab until after the day of fasting, especially clothing that is needed for a celebratory occasion, i.e., a wedding. Now, if one has a wedding (his own wedding, or the wedding of one of his children, for example) immediately after the 9th of Ab, and he or she was unable to buy clothing or other supplies for the wedding before the month of Ab begins, or if the wedding will be held a few days after 9 Ab, but if he won’t buy certain items now, these articles will be more expensive after the 9th of Ab, it is allowed to acquire the items needed for the wedding.
It is also permitted to buy jewelry or clothing when you do it as a business or investment. Because then the acquisition is part of your commercial activity (which does not need to be interrupted during this period) and not a direct function of joy or celebration.
Buying something that is intended for a Mitsva is also allowed. For example, you can buy a new Tefillin or a new book of Tora. You are also allowed to buy non-leather shoes to use during Tish’a Beab.
NETIA SHEL SIMCHA
Our rabbis also forbade “planting for joy”, that is, planting intended for ornamental purposes, such as flowers, myrtle, or other ornamental bushes. Watering or taking care of flowers or ornamental plants, however, is allowed.
Any planting intended for a real practical purpose is permissible. Therefore it is permitted to plant fruit trees in the Nine Days and it is also permissible for a person who earns a living from growing ornamental shrubs and flowers to plant them in order to sell them.
BINYAN SHEL SIMCHA
The Rabbis also forbade to build “a house for the groom”: in the past, the parents will build a small one-room house in their premises for their soon-to-be-married son, and the new couple would use that house for the first year, i.e., until they have a child. Therefore, initiating or continuing the construction of such a house would not be permitted because it is an extension of celebrating a wedding.
Modern rabbis also extended this regulation for other types of buildings and renovations: you should not start any unnecessary renovation or construction in your home, like painting the walls of the house or renovating the kitchen, once the month of Ab begins. However, if you need to build something, for example, you need an extra room for a guest, or you need to fix or renovate something in the kitchen which can not wait until after the 9th of Ab, it can be done. Similarly, if one has already started to build, repair or renovate, one does not need to stop the job during the Nine Days. It is also allowed to build or repair in order to prevent a physical risk, for example, building a fence on the roof or near a window.
Building something that is for the benefit of the community (לצורך רבים) is allowed. It is permitted to build or renovate a Synagogue or a school during the Nine Days.
According to the Sephardic tradition one is allowed to buy, rent or moving into a new house until the beginning of the month of Ab. Now, if by not moving to a new house that one has already bought or rented, one would incur into a significant financial loss, then it will be permitted for to move into the new house during these days (המנהג להורות שלא להיכנס לדירה חדשה, קנויה או שכורה, בתשעת הימים. אבל אם עיכוב הכניסה יגרום להפסד גדול, מותר להיכנס ).
In short, what is forbidden during these days, from the beginning of the month of Ab until after Tish’a beAb, is to do any shopping, acquisition or construction or renovation when it is done primarily for enjoyment or celebration because in order to reach a mindset of “mourning” we need first to disconnect from celebrations and other forms of happiness. However, when we buy or build or renovate or we moved into a new home for necessity, for business or to avoid a significant economic loss, it is allowed.
