For seven days you shall eat unleavened bread, but on the first day you shall remove the leaven from your homes ... you shall guard the unleavened bread, because on this very day I will take you out of the land of Egypt; you shall observe this day for your generations as an eternal decree. - Exodus 12:14-17

Passover is the holiday observed even by the most number of Jews, even the typically non-observant. Pesach begins on the 15th day of Nissan. It is the first of the three key celebrations with historical and agricultural meaning (Shavu'ot and Sukkot are the other two). Though little attention is paid to it, Passover represents the beginning of harvest season. We give most of our attention to the biblical/historical implications from our Exodus from Egypt and slavery.

The root of the Hebrew word Pesach is from Peh-Samech-Chet, the three letters that make up its name. It means to pass through or over, to exempt or to spare and it refers to the fact that God "passed over" Jews’ houses saving Jewish firstborns.

The most important Passover adherence is the removal of chametz, leaven, from our homes. In this, we commemorate the Jews leaving Egypt in such a hurry that bread did not have time to rise. In doing so, we symbolically remove our self-importance and pride to focus on God not ourselves as the cause.

Anything made with grain (wheat, rye, barley, oats and spelt) and not completed cooking in 18 minutes after touching water is chametz. To be 100% certain of following the commandment to rid ourselves of chametz., Orthodox Ashkenazi Jews also avoid rice, corn, peanuts, and legumes as they are used to make bread.

Not only may we not eat chametz, we may not own or derive any benefit from it. Our pets and cattle may not be fed chametz, and utensils used to cook chametz must be thrown or given away or sold to a non-Jew. If pets' diets are not changed, the pets must also be sold to a non-Jew. As with food and utensils, pets may bought back for a token fee after Passover. Chametz can be sold online at www.ChabadCenter.org. This sale is valid under Jewish law and should not be taken lightly.

Cleaning the home of chametz is a huge task that takes weeks including days scrubbing everything, using implements as small as a Q-Tip and toothpick for the stove edges. The morning before the Seder when cleaning is complete, the house is searched for additional chametz. Any found is burned.

Matzah, unleavened bread made from flour and water and cooked quickly so the bread does not rise, is substituted for bread during Passover. This is what the Jews ended up with because of their sudden departure from Egypt.

The Fast of the Firstborn is the day before Passover. It is a minor fast for firstborn males which honors the saving of firstborn Jewish males not killed in the final plague.

On the first night (the first two nights for Jews not in Israel), we have a Seder, from Hebrew meaning order, because meal and prayers are in a specific order.

Pesach lasts for seven days (eight days outside of Israel). No work is permitted on the first and last days (first two and last two outside Israel). We may work on the days in between.

Leviticus 23:15 commands us to count the days from the second night of Passover to the day before Shavu'ot, a full seven weeks. This is called Counting of the Omer. In the days of the Temple, on the second day of Passover, an omer of barley brought to as an offering.

When Passover begins on a motzaei Shabbat, Saturday night after Shabbos ends, preparing for Pesach is changes. Many preparations that are normally done the day before Pesach may not be performed on Shabbat. For example, the Fast of the Firstborn, is moved to Thursday. The search for chametz, instead of the night before Passover is performed on Thursday as well. And the Seder is prepared as much as possible before Shabbat begins. Time should not be spent during Shabbat to prepare for Pesach. An excellent summary is available from the Orthodox Union, the world's most respected kosher certification agency.