Daf 13a

The Mishnah on Daf 13a starts with these words: If one was reading the Torah and the time of reading arrived, if he directed his heart (to have intention to fulfil the mitzvah) then he has fulfilled his obligation.

Everyone should be bothered by the very strange fact that this Mishnah is discussing an extremely rare scenario, that of someone who was reading the parsha of the Shema in the Torah at the exact time when he was to required to read the Shema. Even worse, the gemara says that it refers to one was reading the Torah in an unusual fashion in order to spot mistakes in the writing! And even though we do sometimes find unusual scenarios being taught in the gemara to illustrate a particular point of halachah, this is not normal in the Mishnayos. The following explanation is a possible resolution of this problem:

Since it says in the gemara in Menachos 99b and Nedarim 8a that by reading the Shema in the morning and in the evening one fulfils the essential obligation of Torah study that is mentioned in the posuk in Yehoshua (1,8) "and you shall meditate in it (in the Torah) day and night", it is quite possible that the original Oral Law that Hashem gave to Moshe Rabbeinu was simply to read the Torah in the morning and in the night, but later, albeit very early on, Chazal instituted that this mitzvah of reading the Torah by day and by night was to be fulfilled by the reading of the Shema. This is why the gemara is not certain how much of the Shema one needs to read to fulfil this mitzvah from the Torah.

Thus the text of the Mishnah is the original Oral Law as taught to Moshe, and meant that if one was reading the Torah before the morning or before the evening, and then the time of reading arrives, that is, the time when one is required by the Torah to read the Torah arrives, if one now intends by his reading to fulfil this mitzvah then he fulfils it. This would certainly have been a common occurence. But now that this mitzvah is fulfilled by the reading of the Shema, this teaching is included in the Mishnayos of the laws of reading the Shema. And so, although the original text was retained, it is now interpreted differently, resulting in an unusual scenario.

Daf 13a (contd.)

The Mishnah on Daf 13a continues:

Between the paragraphs (of the Shema) one may greet somebody whom he is required to honour and return a greeting, and in the middle (of a paragraph) he may greet somebody whom he fears and return a greeting - these are the words of R. Meir.

R. Yehudah says: In the middle (of a paragraph) one may greet somebody whom he fears and return a greeting to somebody whom he is required to honour, and between the paragraphs he may greet somebody whom he is required to honour and return a greeting to anyone.

The original Mishnah was:
Between the paragraphs one may greet somebody whom he is required to honour and return a greeting, and in the middle he may greet somebody whom he fears and return a greeting.

This of course is exactly what R. Meir teaches, so what is he arguing with R. Yehudah about? The answer is that they are arguing about how to understand the phrase "and return a greeting", as will become clear from the gemara, which asks that according to R. Meir to whom is he returning a greeting? If it is to someone whom he is required to honour, well, if he may initiate a greeting to such a person then he may certainly return to him a greeting, and so it would be unnecessary for the Mishnah to teach this! Therefore, R. Meir must mean that he may return a greeting to somebody whom he fears. The gemara asks a similar question about whom he may return a greeting to in the middle of a paragraph, and answers that R.Meir must mean that he may return a greeting to anyone.

On this the gemara exclaims: But this is the opinion of R. Yehudah! From this we see that the opinion of R. Yehudah is that logically this must be the explanation of the original Mishnah even though it does not say so explicitly, since otherwise the teaching "and return a greeting" would be unnecessary.

But R. Meir's opinion is explained by the gemara's next words - "the Mishnah was written in an abbreviated fashion". It continues to explain that R. Meir understands that the Mishnah intended to teach "and it goes without saying that he may return a greeting" (to the same type of person to whom he is permitted to initiate a greeting), but was written in an abbreviated fashion.

This then is the dispute between R. Meir and R. Yehudah, with R. Meir preferring to explain that the Mishnah was written in an abbreviated fashion rather than introduce a teaching which was not taught explicitly in the original Mishnah, and R. Yehudah preferring the opposite.

Daf 54a

The Mishnah on Daf 54a says:
One who enters a city prays twice - once when he enters and once when he leaves.
Ben Azzai says four times - twice when he enters and twice when he leaves.
And he gives thanks for the past, and cries out (in prayer) for the future.

The original Mishnah was:
One who enters a city prays twice when he enters and when he leaves. And he gives thanks for the past, and cries out for the future.

But the first clause is ambiguous: if there is a pause after the word 'twice', then it means that he prays twice in total, once when he enters and once when he leaves, and this is the opinion of the first Tanna of our Mishnah; but if there is no pause, then the word 'twice' goes on the phrase 'when he enters' and also on the phrase 'when he leaves', making a total of four prayers, and this is the opinion of Ben Azzai. The last clause of the Mishnah is an additional halachah, and, as we will see, the two opinions implement this additional halachah differently.

The Tosefta, Chapter 6 Mishnah 21, elaborates on the opinion of the first Tanna: What does he say? "May it be Your will Hashem, my G-d, that I will enter in peace." After he enters in peace, he says "I give thanks to You Hashem, my G-d, for bringing me in, in peace. So too may it be Your will that You will take me out in peace." (Here there is obviously a clause missing from the Tosefta, and this is also clear from the Yerushalmi. This is the missing clause:) [When he is leaving he says "May it be Your will…that you will take me out in peace."] After he goes out in peace, he says "I give thanks to You…for taking me out in peace. So too may it be Your will that I will reach my place in peace."

According to the Tosefta, the opinion of the first Tanna is that a person should pray once before he enters the city and once before he leaves. This is the way Rashi explained this opinion in the Mishnah, and not like the Rambam. In addition, after he enters in peace and also after he exits in peace, he should pray for his future welfare, as the last clause of the Mishnah instructs.

The gemara on daf 60a elaborates on the opinion of Ben Azzai - Come and learn. When he enters what does he say? "May it be Your will…that You will bring me into this city for peace." After he enters, he says "I give thanks to You…for bringing me into this city for peace." When he wishes to leave, he says "May it be Your will…that You take me out from this city for peace." After he leaves, he says "I give thanks to You…that You took me out from this city for peace. And just as You took me out for peace, so may You lead me towards peace, and support me towards peace, and guide my footsteps towards peace, and save me from the hand of every enemy and ambush along the way."

According to the gemara, the opinion of Ben Azzai is that he prays once before and after his entering, and once before and after his leaving. Afterwards he fulfils the halachah from the end of the Mishnah with an additional prayer, ackowledging Hashem's help in the past and praying for Hashem's help in the future.

The Yerushalmi on Berachos 66b has a different elaboration of the Mishnah:

One who enters a city prays twice - once when he enters and once when he leaves. When he enters what does he say? "May it be your will Hashem…that You bring me into this city for peace." When he goes out, he says "I give thanks to you Hashem…". This is like the Rambam's explanation of the first Tanna. But the gemara gives no indication how the first Tanna implements the last clause of the Mishnah.

The gemara continues: Ben Azzai says he prays four times - twice when he enters and twice when he leaves. When he enters he says "May it be Your will Hashem…that You bring me into this city for peace." After he enters he says "I give thanks to You Hashem…that I entered for peace. So May it be Your will that You take me out from it for peace." When he goes out he says "May it be Your will Hashem…that You take me out from this city for peace." After he goes out he says "I give thanks to You Hashem…that You took me out for peace. So May it be Your will that You will bring me to my home for peace, and to a certain place for peace." Thus, according to this gemara, Ben Azzai implements the last clause of the Mishnah both after he enters the city, and after he leaves.