Parshas Behar - the mitzva to relinquish produce of shemittah

The passuk says in this week’s sedrah (25:6)

וְהָיְתָה שַׁבַּת הָאָרֶץ לָכֶם לְאָכְלָה לְךָ וּלְעַבְדְּךָ וְלַאֲמָתֶךָ וְלִשְׂכִירְךָ וּלְתוֹשָׁבְךָ הַגָּרִים עִמָּךְ

But you may eat whatever the land during its rest year will produce, you, your slaves and maidservants, the hired workers and the labourers who live with you.

The Rambam says (הל' שמיטה ויובל, ד', כ"ד)

מצות עשה להשמיט כל מה שתוציא הארץ בשביעית... וכל הנועל כרמו או סג שדהו בשביעית ביטל מצות עשה וכן אם אסף כל פירותיו לתוך ביתו, אלא יפקיר הכל ויד הכל שוין בכל מקום שנאמר ואכלו אביוני עמך

It is a mitzvah to allow everyone to take what the land produces during shmittah, and anyone who locks his vineyard or fences his field during shmittah has been מבטל this מצות עשה. And so too if he gathered all his produce into his house. Rather he must be מפקיר everything and everyone has an equal right to it, as the passuk says “And the poor of your people will eat.”

The מנחת חינוך in מצוה פ"ד asks as follows:

When we say that the produce of shmittah is הפקר, do we mean to say that it is a מצוה to make it הפקר, but if someone transgressed and did not make the produce הפקר then in actuality it belongs to him, and if someone else takes it that is considered stealing. Or do we say that the Torah makes the produce הפקר regardless of the intentions of the owner of the field, and if he transgresses and takes it for himself then he has stolen from the public?

The מנחת חינוך demonstrates that this is actually a מחלוקת between the בית יוסף and the מהרי"ט. According to the בית יוסף the produce is not automatically הפקר, rather it is a מצוה for the בעל הבית to make it הפקר. On the other hand the מהרי"ט is of the opinion that the produce of shmittah is automatically הפקר regardless of the intentions of the בעל הבית.

The מנחת חינוך brings a proof for the מהרי"ט from the mishna in Kiddushin (דף נ, ע"ב) that says

...ומעשה בחמש נשים ובהן שתי אחיות וליקט אדם אחד כלכלה של תאנים ושלהן היתה ושל שביעית היתה ואמר הרי כולכם מקודשות לי בכלכלה זו וקיבלה אחת מהן ע"י כולן ואמרו חכמים אין אחיות מקודשות

It happened that there were five women and among them were two sisters, and a man took a basket of figs from their field, during shmittah, and he gave it to one of them who accepted it on behalf of all of them, and he said, “You are all מקודשות to me with this basket of figs.” And the chachamim said that they are all מקודשות except for the sisters.

We see from this mishnah that if women own a field then the produce of that field is הפקר in a shmittah year. If we understand that the Torah makes the produce הפקר, then there is no difference between a field owned by a man and a field owned by a woman. However, if we say that it is a מצוה to make the produce הפקר, and if you were not מפקיר the produce then it belongs to you, then it would appear that this is a מצות עשה שהזמן גרמא which only applies to men and not to women. Therefore the basket of figs which came from the women’s field would not have been הפקר, and it would not have been possible for the man to be מקדש the women with it.

It would be possible to argue, says the מנחת חינוך, that we should not consider the mitzva of shmittah to be a מצות עשה שהזמן גרמא because once the produce acquires the קדושה of שביעית then it is always a מצוה to be מפקיר it, even in the years after shmittah. That means to say, the mitzvah is not considered a מצות עשה שהזמן גרמא because once the mitzvah comes, it is always applicable.

The מנחת חינוך rejects this argument on the basis of the רא"ש who says that if you wear a daytime garment by night, then the garment is חייב in ציצית by night, since its primary purpose is to be worn by day. We know that the gemara classifies theמצוה  of ציצית as a מצות עשה שהזמן גרמא. And we also know that according to the רא"ש, once a garment is classified as a daytime garment, it remains חייב in ציצית always, even at night. You see therefore from the רא"ש that even if a mitzva obligation remains always, nevertheless if the source of the obligation was timebound (such as in the case of ציצית, that the garment is worn primarily by day), then the mitzva is still considered to be a מצות עשה שהזמן גרמא. So too we should say that if it is a מצוה to be מפקיר the produce of shmittah, then even if this obligation always remains, it is still considered to be a מצות עשה שהזמן גרמא. Therefore the מנחת חינוך maintains the proof from the mishna in Kiddushin against the opinion of the בית יוסף.

The אבי עזרי answers the question of the מנחת חינוך from the mishna in Kiddushin as follows:

The mitzva to be מפקיר פירות שביעית is a mitzva that applies to פירות שביעית. Produce that grows during the shmittah year have the קדושה of פירות שביעית, and the mitzva to be מפקיר produce which has the קדושה of פירות שביעית applies forever, because theקדושה  of שביעית remains on the produce forever. Therefore we do not consider this mitzva to be a מצות עשה שהזמן גרמא, and we can explain the mishna in Kiddushin according to the Beis Yosef.

On the other hand, regarding the obligation to wear tztitzis  on a בגד של יום even at night (according to the Rosh), there, the reason that there is an obligation to wear tzitzis on a בגד של יום at night, is because there is a mitzva to wear tzitzis on that garment by day. Specifically, once the obligation to wear tztitzis applies to the garment during the זמן החיוב, then the obligation to wear tztitzis remains, even during night-time, when you would be פטור from tzitzis were you to be wearing a garment whose purpose it is to be worn during that time, at night.

I.e. in the case of tzitzis, time causes there to be a חיוב for you to wear tzitzis by day, and that garment which you became obliged to wear tzitzis on by day retains its חיוב ציצית at night, but the חיוב which applies at night still only originated during the day, which is why the mitzva of ציצית is considered to be a מצות עשה שהזמן גרמא.