Men and women should be separated during prayer services with a mechitza that blocks the men's view of the women. The goal is to keep the men and women from distracting each other during prayer. This idea originated in the Temple in Jerusalem.

When carrying holy books, you may put a Torah or Talmud below other books to prevent their falling or to make them easier to carry.  For piling books on top of each other, see Holy Books: Stacking Order.

“Be holy because I, the Lord your God, am holy.” Leviticus/Vayikra 19:2
 
Halacha ("The Way To Go" or "Way to Walk") guides proper Jewish behavior in all aspects of life, each day of our lives--not just in civil laws or court situations. Halacha teaches us how to behave with our families, relatives, and strangers as well as how to fulfill our religious requirements between ourselves and God.

To fulfill our role as a holy people, we imitate God's actions. Examples are visiting the sick, welcoming guests, giving charity, refraining from creative activity on Shabbat, and promoting peace between husband and wife (shalom bayit).

The true reason for following halacha is because God commanded us to do so.  We observe halacha to please our Creator and to become spiritually close to Him by doing His will and imitating His actions.

Like the word for the whole body of Jewish "laws," each rule of how to act is called a halacha (plural, halachot).

Where Do Halachot Come From?

Although you will find halachot on this site that were born only a few days or a few decades ago, the body of halacha has been around since before creation.  "God looked into the Torah and created the world," says the Zohar, and so we find the Patriarchs followed halacha even before that great law book, the Torah, was given on Mount Sinai four centuries later.
 
Many halachot are specified in the Written Torah (Jewish Bible). These halachot correspond to fuller and more detailed halachot given orally (Oral Torah) to Moses on Mount Sinai to explain the Written Torah that he received at the same time. Many halachot could not be understood from the Written Torah without the Oral Law (for example, what should be written on a mezuza scroll?) and many common practices such as making kiddush or what tefilin should look like are to be found nowhere in the Written Torah.
 
Since the Torah applies to all generations, the Torah specifies that there be wise and learned people to decide how to apply halacha to the situations of the day.  Halachot can be found in sourcebooks such as the Mishna, Gemara, their commentaries, Shulchan Aruch, Mishna Berura, and responsa (questions and answers originally sent by letter and now, occasionally, by email or SMS!) of later rabbis.
 
Sometimes a custom becomes a halacha, sometimes not.  For example, the original halacha for tzitzit was that a Jewish man who wears a four-cornered garment must have tzitziyot on each corner.  The custom, which has become universally accepted and now has the force of halacha, is that Jewish men wear a four-cornered garment in order to be able to fulfill the commandment of wearing tzitziyot.  An example of a custom that did not become a halacha is that some men and boys wear their tzitziyot outside of their shirts and pants.

Levels of Halachot

In halacha, there are three levels of what to follow or observe. They are differentiated on this website by the following terms: 

• “Must”:  Halachot that are generally non-negotiable except in extreme situations;
• “Should”:  Customs that have been accepted by the entire Jewish world (or major segments of it) and that may be overridden when necessary, sometimes even if not extreme circumstances; and
• “Non-Binding Custom”:  Customs that are not universally followed and that do not need to be followed except by people who have the tradition to do so.

You do not need an eruv chatzeirot if you are in an apartment building even without a central kitchen but where:

• The building owner has property in each apartment, and
• The building owner or manager has the ability and the right to enter your apartment and the other apartments.

 

Writing a Torah scroll (sefer Torah) is a mitzva but is not a priority; there are other activities that have a higher priority for Jewish observance.

Only three of the Four Sons' questions are mentioned in the Torah (which all related to the Passover sacrifice), since the fourth (smallest) child cannot ask questions. Regarding this child, the hagada says, "Aht p'tach lo" (in the feminine).
Reason  The mother is supposed to be a child's primary teacher while the child is young.
There is a difference in attitude between the wise son and the evil son: The wise son says "Eloheinu" (OUR God); he is asking a question and seeking and answer. The evil son makes a statement (sort of a rhetorical question), instead of asking a question for which he seeks an answer. Yet, regardless of the sons' level of observance, it is a commandment to teach them about going out of Egypt.

L'chatchila, you should not bake uncovered dairy and meat foods in the same oven at the same time, even if both pans:

• Are non-liquid, AND
• Do not touch each other.

B'di'avad, both uncovered pans remain kosher—even if they touch each other, if both pans:

• Are non-liquid,
• Are clean and dry (on the outside), AND
• Do not contain spicy/charif food.

There are four mitzvot for Purim:
1. Shalach Manot (Gifts of food to promote friendship)
Send to one person at least two readily edible foods that will be appreciated by the recipient. Sending gifts of food (mishlo'ach manot) must be done on Purim day. The earliest time to send mishlo'ach manot is after hearing the morning megila reading (so that the commandment of giving gifts to friends is also covered by the blessing of she'hecheyanu over the megila).

2. Gifts to Poor People
Give some money to at least two poor people or to a fund designated to give to poor Jews on Purim. The earliest time in the day to give gifts to the poor on Purim is daybreak.

3. Hearing the Megila Twice (evening and morning)

• If you miss hearing a word or even syllable of the megila on Purim, say it to yourself and then catch up to the reader.
• If you are not near a minyan and do not have a megila scroll, you should read the megila from a book.  But you will not have fulfilled the commandment of reading the megila and so you do not say any of the blessings.

4. Eating at a Purim se'uda.

• The minimum amount to eat and drink for a Purim meal is at least 1.3 fl. oz. (39 ml, or 1/6 cup) of bread, any amount of meat (if you enjoy meat), and some wine (any amount more than you normally drink).
• The earliest time you may eat the Purim meal is from daybreak; the latest time you must begin is before sunset.  You must eat at least 1.3 fl. oz. (39 ml, or 1/6 cup) of bread and some wine (and meat if you enjoy it) before sunset. You may continue your meal after sunset as long as you ate the bread before sunset.

 

After the blessings have been said:

• Pour some wine from the two cups into a third cup.
• Pour some wine back into the first two cups.
• The bride, groom, and person who made the blessing each drink from a different cup.

Note Each cup will contain some wine from each of the original two cups on which the blessings had been made.

The Five Special Fruits do not combine in volume with non-special fruits for the after-blessing of al ha'eitz if eaten sequentially or even interspersed with each other.
Example
Situation
You ate a date and then ate the remainder of 1.3 fl. oz. (39 ml, or 1/6 cup) of cherries.
What To Do
Say:

• Fore-blessing of borei pri ha'eitz over the date (and cherries).
• After-blessing of borei nefashot on all the fruits.

Although the Five Special Fruits do not combine in volume with non-special fruits for the after-blessing of al ha'eitz if eaten sequentially or even interspersed with each other, they DO combine for the after-blessing if:

• They are considered to be one food, AND
• The main component is the Special Fruit.

Example
                        Situation
You eat at least 1.3 fl. oz. (39 ml, or 1/6 cup) within four minutes of dates stuffed with almonds.
What To Do Say the after-blessing of al ha'eitz over both types of fruits.

Light Chanuka candles in your own house, unless you are not in the city in which you live.

Before Shabbat, we make or buy the food that we will need for Shabbat. Although cooking is forbidden on Shabbat, some food preparation is allowed after Shabbat begins. See Shabbat: Cooking.
Special Shabbat foods include two loaves of bread for each of the first two meals and, preferably, for the third meal, too. 
 

To avoid making a blessing in vain (bracha l'vatala), you may intend a fore-blessing to cover all other foods of that category that you will eat at the same time.