Why does 53: consider israel land belonging to Yidden on sole merit of promise to Avrohom before actual inhabitance, in contrast to the pasuk in lech lecha 13:7 saying it then belonged to Canaanim and Prizi and that was the basis for rebuking Lot's shepherds that they were stealing in grazing their flocks in EY?
I'm thinking this: the promise to Avrohom to give him EY was to him and his zera. Perhaps it only gets the status of becoming his (and the Yiddens) after Avrohom had zera- Yitzchok, which is the time period of today's daf discussion. But, at Lots time of Shepherd argument, Yitzchok hadn't been born, so the lands ownership status then was still of goyim.
Rashi there makes two points why lots claim was invalid- 1) he's not the zera and it's currently eretz Haamim. The mefarshim deal with explaining rashis use of both points. Our above answer could also serve to explain why Rashi makes both points- they are intertwined according to this pshat (vs other pshatim that describe two independent arguments against Lot).
Daniel Gray, Canada
1) Yes, I agree with you Daniel. Eretz Yisrael did not actually belong to Avrohom Avinu, only to his zera. This is in fact stated by Rashi Bereshis 13:7; that E.Y. was given to Avrohom but he has no-one to inherit him yet. Rashi writes that Avrohom had not yet been zocheh in EY.
2) Rashi Bereshis 12:6 writes that the Cananites were at that time conquering EY from the descendants of Shem. EY had fallen to the seed of Shem when Noach divided up EY between his 3 sons. Therefore Hash-m promised that He will in future return EY to the sons of Avrohom who are the rightful owners, because they are descended from Shem.
3) One learns from Rashi Bereshis 15:18 that EY already belonged to Yitzchak. Hash-m said there to Avrohom "I have given this land to your seed". Rashi writes that when Hash-m says something this means it is as if it has already happened. The Talmud Yerushalmi Chalah 2:1 explains that since Hash-m did not say "I will give it to your seed" but rather "I have given it to your seed" this means it has already been given.
KOL TUV
Dovid Bloom
I found that the Or Hachaim explains how and when Avraham and Yitzchak gained Eretz Yisrael.
1) Bereshis 13:15 tells us that Hashem said to Avraham "For all the Land that you see I will give to you and to your seed for eternity". Or Hachaim writes that it is clearly a miracle that Avraham was able to see the entire Eretz Yisrael. He writes that there is no greater Chazaka than Hashem folding up the Land so that Avraham could see it all.
2) Seeing the entire Land was therefore a chazaka whereby Avraham himself received Eretz Yisrael. We should note that the above verse 13:15 comes between 13:7 and 15:18. Verse 13:7 is where Rashi writes that Avraham had not yet gained Eretz Yisrael. Verse 15:18 is where Hashem says "I have given this Land to your seed"; which we saw that the Talmud Yerushalmi Chalah explains to mean that "I have already given it". Based on the above Or Hachaim we are now in a position to assert that the exact point in time where Avraham received Eretz Yisrael was when Hashem showed it all to him in 13:15.
3) Bereshis 26:1 tells us that Yitzchak went to the Land of Plishtim. 26:3 tells us that Hashem said to Yitzchak "to you and your seed I will give all these lands". Or Hachaim there cites Ramban that Plishtim is included in EY. Or Hachaim adds that it may be that Avraham's original Chazaka did not include the land of Plishtim. However Yitzchak now made a complete Chazaka on Plishtim by plowing and sowing seeds there.
4) According to Or Hachaim we can say that Rashi Avoda Zara 53b DH v'Ashereihem can be taken according to its simple meaning. Eretz Yisrael is an inheritance to them from their forefathers because Hashem told Avraham that He would give it to him, and indeed He did give it to Avraham himself.
5) We will just note that the Yerushalmi Challah cited above also states " even before they entered Eretz Yisrael they had inherited it lemafraya". See also Bavli Bava Basra 119a which states that Eretz Yisrael is "Muchzekes". Rashbam DH Muchzekes explains that the Bnei Yisrae,l who left Egypt, already had a part of EY because Hashem had already given it to them as an inheritance.
Yasher Koach
Dovid Bloom
The Hebrew Mesivta cites Parshas Derachim (Derush #9) by the author of Mishneh l'Melech, who asks your question, Daniel.
1) The answer of Parshas Derachim is based on Tosfos Rosh Hashanah 13a DH v'Lo. The Gemara there states that the Bnei Yisrael could not have brought the produce of Nochrim for the korban Ha-Omer, after they entered EY but before they conquered it, because we derive from a pasuk that what a Nochri reaps, and thereby belongs to him, is invalid for korban Ha-Omer. Tosfos asks on this from our Gemara that Eretz Yisrael is an inheritance for Klal Yisrael from the forefathers. How then can we say that when a Nochri reaped produce before EY was conquered that it belonged to him; the Gemara Avoda Zara 53b states that Bnei Yisrael already inherited it from the time of Avraham?!
2) Tosfos answers that even though EY was an inheritance for Klal Yisrael from their fathers, nevertheless the Nochri does own the produce that he sows in the land. This can be understood by saying that whilst Avraham had a kinyan ha-goof in EY, the Canaanites and Prizites had a kinyan peiros; they owned the produce that they cultivated from the fields.
3) When did EY become totally the possession of Avraham and his seed? Parshas Derachim answers with the Midrash Rabah Bereshis 41:5. Hakadosh Boruch Hoo said "I said 'to your seed I have given the land'. When will that be? When the 7 nations will be uprooted from EY". But for the moment the verse states 'and the Cananite and Prizite were still in the Land'. The 7 nations still had a stake in the Land.
4) According to this, when Rashi Bereshis 13:7 wrote "Avram had not yet received EY", this means that he has received the kinyan ha-goof but the Cananites and Prizites still eat the produce. It is only when the 7 nations were uprooted from the Land, that the seed of Avraham received the kinyan peiros as well.
Dovid Bloom
Thank you Dovid. Prior to receiving your replies, I went over the pesukim and Rashi on the bris bein habisarim and noted that all the pesukim and Rashi were very meduyak and had also noted "venasatei" that Hashem had already given (as you too noticed and pointed out), and that aside from Avrohom being gifted EY, there was a separate calculation regarding the expulsion of the Goyim and that the sins of the Canaanim and Prizi had not yet reached the level where they could be expelled. Two concurrent calculations - when the gift kicks in as well is when expulsion is deserved and due.
The 400 years of galus starting with when Yitzchok was born and Avos were Gerim by living in lands not theirs - is meduyak that it's not saying they didn't own the land in some way (for example, plug in either of your two reply email explanations), but rather that living in a land where they didn't have full rights at that time (for example, plug in either of your two reply email explanations and if using your first email reply, you can join with it my above comment that the Canaanim and Prizi had not yet reached the level where they could be expelled) and to that end it was referred to a land not theirs and thus gave them a status of a Ger in that land, as to have a status of a full-fledged owner needs full-fledged rights in the land without limitation.
Daniel
Hashem said to Avraham Avinu (Bereshis 15:13) that his seed would be Gerim in a land - Egypt - that did not belong to them. This implies that Eretz Yisrael was already considered as a Land that belonged to them. This fits in well with Tosfos Rosh Hashanah 13a DH v'Lo that they already owned the Land of Yisrael, even though they did not yet own the produce that grew from it.
Behatzlacha Rabah
Dovid Bloom