The observance of the Passover religious holiday within the Jewish religion is one of the very strict rituals. There are several rules that must be adhered to.
For starters, in remembrance of the Israelites hasty departure from Egypt, all leavening is forbidden during Passover. And it’s just not the consumption of leavened bread that is forbidden, but also the keeping and owning of any leavened products during the Passover feast is not permitted. Therefore, in preparation of the Passover festival all leavened products are either eaten or given away to non-Jews. It’s important to note that fermentation and yeast are not only allowed, but are in fact required during the Passover ceremonious celebrations. On the night before Passover begins a blessing is read and then a traditional search is done through the house for any remaining chametz (leavened bread). During the days leading up to this eve, 10 morsels of bread that can be no larger than an olive are hidden throughout the house to be found and subsequently burned the next day, as part of the formal tradition.
Another ritualistic observance is that any dish, glass, or silverware that has ever touched chametz is packed up during the cleaning process and only special dishes, etc., are used during the Passover feast. It is also permissible to boil the utensils to remove any chametz from them.
Matzo is highly regarded and serves a key function in the Passover observance. It is preferred to eat matzo on the first night of Passover and then to only eat unleavened bread throughout the week of Passover.
The Passover feast lasts for seven or eight days, depending upon one’s Jewish tradition. The first night of Passover is the most reverent, containing a special dinner noted as a Seder. The book entitled Haggadah is used in the feast and is strictly and solemnly adhered to. The book tells the story of the Exodus from Egypt and has 15 phases that unfold throughout the night’s retelling. There are four cups of wine consumed throughout various parts. The 15 parts are: a blessing and the drinking of the first cup of wine; washing of the hands; dipping the karpas in salt water; breaking of the middle matzo; retelling of the Passover story, recital of the four questions and drinking of the second cup of wine; second washing of the hands, this time with a blessing; a traditional blessing before eating bread; blessing before eating matzo; eating of the maror; eating of a sandwich made of matzo and maror; serving of the holiday meal; eating of the afikoman; blessing after the meal and drinking of the third cup of wine; reciting of the Hallel and drinking of the fourth cup of wine; conclusion with songs and prayer. The 15 parts represent the 15 steps in the Temple in Jerusalem where the Levites stood during Temple services, also memorialized in the 15 Psalms.
As you can see, Passover is held as the most religious and ceremonious celebration of one of the three holiest of the Jewish holidays.