ערב שבת בשביעית ואומר מכאן אני אוכל למחר וחכמים אומרים עד שירשום ויאמר מכאן ועד כאן:
on Shabbat eve during the Sabbatical Year, during which no tithes are separated, which means one may take fruit on the following day without the need for any corrective measure, and say: From here, from these fruits, I will eat tomorrow. And the Rabbis say: He may not eat unless he marks the pile of fruit the day before and explicitly says: From here to there I will take.
גמ׳ תנן התם תינוקות שטמנו תאנים מערב שבת ושכחו ולא עשרו למוצאי שבת לא יאכלו אלא אם כן עשרו ותנן נמי המעביר תאנים בחצרו לקצות בניו ובני ביתו אוכלין מהן עראי ופטורים
GEMARA: We learned in a mishna there: (Ma'asrot 4:2) Children who hid figs for themselves in a field on Shabbat eve in order to eat them on Shabbat, and they forgot and did not separate tithes, not only are they prohibited from eating them on Shabbat, for eating on Shabbat is always considered a fixed meal that obligates the produce in tithes, but even after the conclusion of Shabbat, they may not eat until they have separated tithes. And we also learned in a mishna: One who transfers figs in his courtyard in order to make them into dry figs, his children and the members of his household may in the meantime partake of them in a casual manner, and they are exempt from tithes. The fact that the fruit has reached his courtyard, as opposed to his house, is not enough to cause it to be liable for tithing.
בעא מניה רבא מרב נחמן שבת מהו שתקבע מוקצה למעשר בדבר שלא נגמרה מלאכתו מי אמרינן כיון דכתיב (ישעיהו נח, יג) וקראת לשבת עונג קבעה ואפילו בדבר שלא נגמרה מלאכתו או דלמא בדבר שנגמרה מלאכתו קבעה בדבר שלא נגמרה מלאכתו לא קבעה
Based on these two sources, Rava inquired of Rav Naḥman: With regard to Shabbat, what is the halakha in terms of whether it establishes an obligation to tithe food that has been muktze on Shabbat? Specifically, in the case of an item whose labor has not been completed,does the fact that the food is muktze on Shabbat give it the status of completely prepared food, or not? Do we say that since it is written: “And call Shabbat a delight” (Isaiah 58:13), this implies that any food one eats on Shabbat is considered a delight and not a casual meal, and therefore Shabbat establishes an obligation to tithe, as if the food were fully completed and fit to be eaten as a fixed meal, even for an item that has not had its labor completed? Or perhaps Shabbat establishes an obligation to tithe an item whose labor is completed, but regarding an item whose labor is not completed it does not establish an obligation to tithe?
א"ל שבת קובעת בין בדבר שנגמרה מלאכתו בין בדבר שלא נגמרה מלאכתו א"ל ואימא שבת דומיא דחצר מה חצר אינה קובעת אלא בדבר שנגמרה מלאכתו אף שבת לא תקבע אלא בדבר שנגמרה מלאכתו א"ל לימוד ערוך הוא בידינו שהשבת קובעת בין בדבר שנגמרה מלאכתו בין בדבר שלא נגמרה מלאכתו
Rav Naḥman said to Rava: Shabbat establishes the obligation for tithes, both with regard to an item whose work is completed and things whose work is not completed. Rava said to Rav Naḥman and challenged: But say that the law of Shabbat should be similar to that of a courtyard: Just as a courtyard establishes food placed inside it as a fixed meal with regard to tithes only when the work on an item is completed, so too, Shabbat should establish only an item whose work is completed as liable for tithing. Rav Naḥman said to Rava: I did not say this based on my own logic, which can be countered by logic of your own. Rather, we have it as an ordered teaching that Shabbat establishes both things whose work is completed and things whose work is not completed.
אמר מר זוטרא בריה דרב נחמן אף אנן נמי תנינא ועוד אמר רבי אליעזר עומד אדם על המוקצה ערב שבת בשביעית וכו' טעמא דשביעית דלאו בר עשורי הוא הא בשאר שני שבוע הכי נמי דאסור מ"ט לאו משום דשבת קבעה
Mar Zutra, son of Rav Naḥman, said: We, too, have learned in the mishna: And Rabbi Eliezer further stated that a person may stand over objects in the storage area on Shabbat eve during the Sabbatical Year and say: I will eat from here and here. The reason is that it is fruit of the Sabbatical Year, with regard to which one is not obligated to separate tithes. However, if it occurred in the other years of the Sabbatical cycle, so too, you will say that it is prohibited to eat them without separating tithes. What is the reason for this? Is it not because Shabbat establishes them with regard to tithes, and consequently they not be eaten until tithes have been separated?
לא שאני התם כיון דאמר מכאן אני אוכל למחר קבע ליה עלויה אי הכי מאי אריא שבת אפילו בחול נמי הא קמ"ל דטבל מוכן הוא אצל שבת שאם עבר ותקנו מתוקן
The Gemara refutes this: This is no proof, for there it is different: Since he said: From here I will eat tomorrow, he has immediately established for himself a meal with them, by stating his intention to eat the food as it is. The Gemara asks: If so, why does the mishna mention particularly Shabbat? Even if one said so on a weekday the same should also apply. Since he has set them aside for his meal, they are considered finished and are liable to tithes. The Gemara answers: This comes to teach us the following: One should not conclude that untithed produce is inherently muktze because one may not separate the tithes and eat it; rather, it is considered prepared with regard to Shabbat, in that if one transgressed the words of the Sages and corrected it by separating the tithes, it is considered corrected.