Is shmita nowadays deraisa or derabon and why? I have heard different reasons its derabon (you need bias kulchem and all Jews have to be in Israel, you need the shevatim to be sitting in their respective teriories, we have no urim veturim) but don know which ones are true and not true.
Also my undertanding (which might also be wrong) is that shevis is dependent on the borders of Yehoshua nd terumas and missar go after the borders of Ezra. Is this true and if it is why should there be a differnce?
Thank you for your response
kerfish,
This is a very large topic and I will just try to make a quick start on it for now, bs'd.
I will first relate to some sources for the ideas that you have heard mentioned.
1) Rashi here (36a, DH bi'Shevi'is) writes that Abaye held that in the time of the second Beis ha'Mikdash, since Yovel did not apply it follows that Shemitah also did not apply mid'Oraisa. Tosfos here (DH ba'Zman) writes that the fiftieth Yovel year did not apply in the time of the second Beis ha'Mikdash because a majority of the Jewish people did not live in Eretz Yisrael. This may be a source for the opinion that Shemitah is only d'Rabanan nowadays, since we do not have Yovel because we are missing "Bi'as Kulchem."
2) The source that the Shevatim need to be dwelling in their respective territories may be from the Gemara in Erchin, end of 32b, which states that even if the Shevatim are in Eretz Yisrael, but the tribe of Binyamin is mixed up with the tribe of Yehudah or vice versa, the Yovel does not apply, because the Torah requires that the Shevatim all dwell in the proper way. If we say that Yovel and Shemitah go hand in hand, this would be a source that Shemitah is not d'Oraisa now.
3) There may be a source from the Meshech Chochmah (Bamidbar 35:13) that there cannot be Shemitah d'Oraisa without the Urim v'Tumim. He discusses why the 42 Levite cities did not apply in the time of the second Beis ha'Mikdash. He also writes that it may be that for the same reason (there were no Levite cities then), Terumos and Ma'aseros were not mid'Oraisa in the time of the second Beis ha'Mikdash. The Meshech Chochmah concludes that it may be that because Eretz Yisrael in the time of the second Beis ha'Mikdash was not divided up using the Urim v'Tumim, all of these things did not apply mid'Oraisa.
According to this, one could claim that this is a reason why Shemitah is not d'Oraisa now.
I will close here for the moment, but what I have written is really just the tip of the iceberg.
Kol Tuv,
Dovid Bloom