887. Eating and Drinking Before Kiddush and Havdalah

Shabbos 29:5

It is prohibited to eat or to drink wine from the time Shabbos begins until one recites kiddush. Similarly, once Shabbos ends, it is prohibited to start eating, drinking, performing acts of labor or to taste anything until havdalah is recited. Drinking water is permitted. If one accidentally or intentionally eats or drinks before kiddush or havdalah, he still recites kiddush or havdalah after.

Shabbos 29:6

The Sages enacted that we should recite kiddush and havdalah over cups of wine. Even though a text that serves as havdalah is recited at maariv, one is nevertheless obligated to also recite havdalah over a cup. However, once a person has said "Blessed is the One Who divides between the holy and the mundane," he is permitted to perform acts of labor even though he has not yet recited havdalah over a cup. The blessing over the wine is recited before the blessing of kiddush. One should not wash his hands until after kiddush.