Washing Dishes on Shabbat
Is it permissible to wash the many dishes that accumulated after the third meal of Shabbat?
Answer: In Tractate Shabbat (page 118a), we learned that it is forbidden to prepare from Shabbat for weekdays. In other words, it is forbidden to do something on Shabbat when there is no need for it on Shabbat itself. For example, it is forbidden to heat food on Shabbat for the purpose of after Shabbat, and similarly with other such activities.
It is thus explained in Tractate Shabbat (ibid) that it is forbidden to rinse (wash) dishes on Shabbat when doing so for the purpose of after Shabbat. That is, one should not wash dishes on Shabbat when they are not needed for Shabbat itself. The reason for the prohibition, as written by the Raavad, is so that a person does not toil on Shabbat for something that is not for the honor of Shabbat itself.
Washing Dishes After the Third Meal
Maran the Shulchan Aruch (Section 323) wrote in these words: "One may wash dishes (on Shabbat) for the needs of the day. For example, if one still has another meal to eat. But after the third meal, one should not wash dishes. And drinking vessels may be washed all day, since drinking is appropriate throughout the day."
Washing Cups
From these words we learn that drinking vessels, such as cups and the like, may be washed even after the third meal, since it is entirely possible that these vessels will be needed even after the meal. However, meal utensils, such as plates, cutlery, and the like, should not be washed after the third meal.
Washing Cups After Sunset
It is obvious that if they ate the third meal at a late hour, until they finished it after sunset, it is forbidden to wash cups and other drinking vessels after the meal, since it is forbidden to drink after the meal (after sunset) until they make Havdalah as required.Washing Dishes After the Third Meal When They Are Still Needed
Similarly, the opposite is true regarding meal utensils, such as plates and cutlery. If the third meal was eaten very early, and they want to use the meal utensils again afterward, it is permitted to wash them even after the third meal. For all the prohibition in this matter is only because, generally, after the third meal, these utensils will not be used again, but if it is known that these utensils will be used again, it is permitted to wash them on Shabbat.
In Summary: It is permitted to wash dishes on Shabbat when these dishes are needed for Shabbat itself. But after the third meal, when it appears that there is no more need for the meal utensils, it is forbidden to wash the dishes. However, cups that are used for drinking may be washed even after the third meal (before sunset), since it is possible that they will be used on Shabbat itself.
Rulings of Rabbi Ovadia Yosef, courtesy of the "Daily Halacha" website
