Kiddush is a blessing recited over wine or grape juice to sanctify the Shabbat, Yom Tov or a Bat Miztvah or Bar Mitzvah ceremony. The Torah refers to two requirements concerning Shabbat - to keep it and to remember it (Shamor and Zachor). Jewish law therefore requires that Shabbat be observed in two respects. One must "keep it" by refraining from thirty-nine forbidden activities, and one must remember it by making special arrangements for the day, and specifically through the kiddush ceremony.
Reciting kiddush before the meal on the eve of Shabbat and Jewish holidays is thus regarded as a commandment from the Torah (as it is explained by Talmud Bavli). Reciting kiddush before the morning meal on Shabbat and holidays, however, is a requirement of rabbinic origin. Kiddush is not usually recited at Shalosh Seudos, although The Rambam was of the opinion that wine should be drunk at this meal as well.
In this section, find a great selection of Kiddush cups - the cup used to hold the wine during the Kiddush ceremony.