לרפואת א"מ הענא מרים בת חנה בתוך שח"י ולהצלחת חיילי צה"ל
Two more proofs that the hefker of Shmitta is not humanly activated, אקרקפתא דגברא, but rather אפקעתא דמלכא - a Divinely ordained hefker.
1] In the Yerushalmi Peah [5/1] there is a discussion if hefker beis din absolves one from the obligation to give maaser. [The Chazon Ish explains the safek of the gemara as being whether hefker beis din is a bona fide hefker that devolves on the cheftza of the fruits or maybe it is only a din on the gavra, that the person must relate to his fruits as if they are hefker and there is no issur gezel but in reality they are still his and he must separate maaser.] The gemara proves from the added month in a leap year in the seventh year of shmitta that he is patur from maaser, for in this case it is hefker beis din [for they added the extra month] and he is patur, so too, in any case of hefker beis din . The gemara then rejects this proof and says that adding a leap year is actually not a case of hefker beis din but mi-dioraisa [see there with the commentary of the Mahar"a Fulda].
If you assume that the law of hefker on Shmitta is אקרקפתא דגברא, how could the gemara logically compare hefker beis din to the added month of the leap year? The added month of shmitta is אקרקפתא דגברא while hefker beis din is the doing of beis din?! This compels us to conclude that Shmitta is indeed אפקעתא דמלכא - coming from a higher source and can thus be compared to hefker beis din which is also coming from a higher source. This proof was cited by the Chazon Ish in the name of the Radbaz and he said that it is a ראיה אלימתא - a very powerful proof.
2] In Nedarim [42b] the gemara says that if one is מודר הנאה [forbidden to derive benefit] from his friend, on shmitta he may eat his friend's fruits because they are hefker but he may not enter his friend's field. The gemara asks why this is so. Just as his fruits are hefker, so is his field? The gemara offers two answers: 1] The fruits are on the border of the field and the field is only hefker for the pupose of picking the fruit, so it is not necessary to enter the field. 2] There is a decree forbidding him from entering the field, lest he enter for longer than necessary in order to pick the fruits.
A simple reading of the sugya would indicate that the hefker status of the field is a general one and not dependent on the will of the owner [even though the language of the gemara is אפקרה, which means that the owner was mafkir, nevertheless the text of the Ran and others reads "רחמנא אפקרה"].
From all of these proofs concludes the Minchas Asher [Shviis 7] that EVERYBODY holds that hefker peiros shviis is not at all dependent on the hefker of the owner but a Divine mandate - אפקעתא דמלכא. Let us carefully examine the language of the Beis Yosef "אע"ג דרחמנא אפקרה כיון דאיהו לא אפקרה חייבת". It is clear that he holds that Hashem is doing the hefker. What the Beis Yosef holds is that if the owner is not mafkir the field and locks it up then the fruits are חייב in trumos and maasros [even though מדין תורה the fruits are hefker].
The explanation is as follows: If someone makes his field hefker and then locks the field up and allows nobody to enter, the fruits will be patur from maaser since the fruits are hefker. But Shviis is different because the Torah did not remove the field from the person's possession in the seventh year. The Torah just permitted anyone to come and take from the fruits. Hashem doesn't need to remove the field from a person's possession in order to allow people to take. In the seventh year the field remains in the owner's possession but anyone is allowed to enter and help themsleves. Since there is not a monetary, mammonis-dik removal from the owner, the Beis Yosef was mechadesh that if the owner doesn't allow people to enter the fruits remain obligated in maaser. If it were hefker gamur then it would be a different story. Whether people may enter or not doesn't matter because the fruits have no owner. This is then included in the drasha of the gemara that says that one must give shevet levi the fruits because he has no portion in the land [כי אין לו חלק ונחלה עמך]. But if the fruits are completely hefker then he DOES have a portion and the fruits are thus patur from maaser. But on shmitta where the land is formally still in the possession of the owner and he also refuses to comply with the din Torah that he must let everyone in, we cannot say that the Levi has a portion and the fruits are patur from maaser. No way! The fruits are the owners and the Levi is practically being refrained from entering. Hence, the ptur from giving maaser doesn't apply.
This also explains the gemara [Peah 6/1] that says that on Shviis the fruits are hefker for the animals as well. How is it possible to talk about monetary rights for animals [such as Hamas...]? The answer is that the hefker we are discussing here is not a formal, legalistic type of hefker but a practical "Let everyone in to eat your fruits". This can apply to animals as well. Even according to this thesis, if the person WAS mafkir the field and let eveyone in, the field becomes a mamoness-dike full-fledged hefker.