Question (Beraisa - R. Shimon ben Elazar): R. Meir would write Mezuzos on Duchsustus. (Hide has two layers that can be peeled apart. The inner layer, i.e. closer to the flesh, is called Duchsustus. Rashi (elsewhere) and Tosfos explain like this. This is why Shitah Mekubetzes corrects the text of Rashi.) The shape of the writing was (long and thin), like a column;

He left a space above and below, and made the Parshiyos open.

R. Shimon ben Elazar: Why did you make them open? (They are closed in the Torah!)

R. Meir: I made them open because they are not adjacent in the Torah.

(R. Chananel citing Rav): The Halachah follows R. Shimon ben Elazar.

Summation of question - suggestion: The Halachah follows him (even) regarding open Parshiyos. (Rav Huna was a Talmid of Rav. Surely, he conducted like Rav!)

Answer: No, Rav ruled like R. Shimon ben Elazar (only) regarding the spaces above and below.

Question: How much space must be left?

Answer (Rav Menasiya bar Yakov): He must leave the size of the clamp (to hold down the corners of the parchment).

Abaye (to Rav Yosef): Don't you agree that Rav did not rule like R. Shimon regarding open Parshiyos?!

Rav says that the custom prevails, and the custom is to make the Parshiyos closed!

(Rabah citing Rav): If Eliyahu will come and tell us that we may use a Min'al (a soft shoe) for Chalitzah, we will heed him. If he will tell us that we may not use a Sandal (a hard shoe), we will not heed him, for the custom is to use a Sandal;

(Rav Yosef citing Rav): If Eliyahu will tell us that we may not use a Min'al, we will heed him. If he will tell us that we may not use a Sandal (a hard shoe), we will not heed him, for the custom is to use a Sandal;

Question: What is the difference between these versions?

Answer: Rav Yosef permits using a Min'al l'Chatchilah. Rabah holds that it may not be used l'Chatchilah.

Conclusion: (According to both versions, Eliyahu cannot abolish the custom to use a Sandal.) This proves that Rav holds that that the custom prevails.

(Rav Nachman bar Yitzchak): L'Chatchilah, the Parshiyos should be made closed. R. Shimon ben Elazar teaches that even open Parshiyos are Kosher.

Support (Beraisa): If (parchments of) a Sefer Torah or Tefilin became worn, they may not be used for a Mezuzah, for we do not demote something to a lower Kedushah.

Inference: If it were permitted to demote to a lower Kedushah, they could be used for a Mezuzah, even though the (first) Parshah (in a Mezuzah, Shma Yisrael) is closed!

Rejection: (No. Even if it was permitted to demote Kedushah, we could not use both Parshiyos from the Torah, for Shma is closed in the Torah.) Because we do not demote to a lower Kedushah, even one Parshah may not be used (even if he would attach it to the other Parshah, making an open break between them - Rashba). Alternatively, the question assumed that the Beraisa would permit using an entire Parshah (if not for demoting the Kedushah), even though each of them is closed. The rejection says that perhaps the Beraisa discusses using one line of a Parshah.)

Question: May we really infer that if it was permitted to demote Kedushah, they could be used for a Mezuzah?!

(Beraisa #1): A tradition from Moshe from Sinai teaches that Tefilin are written on Klaf (the outer layer of hide), and Mezuzos are written on Duchsustus.

On Klaf, we write on the inner side (that faced the flesh). On Duchsustus, we write on the outer side (that faced the hair).

Answer: That is l'Chatchilah. (B'Di'eved, a Mezuzah on Klaf is Kosher.)

Question (Beraisa #2): If one deviated, it is Pasul.

Answer: That refers only to writing Tefilin on Duchsustus. (A Mezuzah on Klaf is Kosher.)

Question (Beraisa #3): If one deviated in either of these, it is Pasul.

Answer #1: This refers to writing Tefilin on the wrong side of either parchment, i.e. on the outer side of Klaf or on the inner side of Duchsustus. (One may not use either side of Duchsustus. Beraisa #2 disqualified the outer side. One might have thought that Tefilin are Kosher on the inner side, like we find regarding Klaf.)

Answer #2: Tana'im argue about writing Tefilin or Mezuzos on the wrong kind of parchment. (Beraisa #1 is like R. Acha.);

(Beraisa): If one deviated (wrote on the wrong kind of parchment) in either of these (Tefilin or Mezuzos), it is Pasul;

R. Acha is Machshir.

Question: May we really infer that if it was permitted to demote Kedushah, parchments of a Sefer Torah or Tefilin could be used for a Mezuzah?!

Mezuzah requires Sirtut (lines scratched in the parchment to help the scribe write straight. Tefilin (Tosfos - and Sifrei Torah) do not require Sirtut, therefore, normally, they do not have Sirtut!)

(Rav Minyomi bar Chilkiyah citing Rav): A Mezuzah without Sirtut is Pasul.

(Rav Minyamin): A tradition from Sinai requires Sirtut in a Mezuzah.

Answer: Tana'im argue about whether a Mezuzah requires Sirtut.

(Beraisa - R. Yirmeyah): Tefilin and Mezuzos may be written by memory (without written parchments in front of him). They do not require Sirtut.

The Halachah is, Tefilin does not require Sirtut, but Mezuzah does. Both may be written by memory.

Question: What is the reason (for the second law)?

Answer: People know the Parshiyos well. (They will not err.)

(Rav Chelbo): I once saw that Rav Huna wanted to sit on a bed on which a Sefer Torah was resting. He stood up a barrel and put the Sefer Torah on it, and then sat on the bed.

He holds that one may not sit on a bed on which a Sefer Torah rests. He argues with Rabah bar bar Chanah;

(Rabah bar bar Chanah): One may sit on a bed on which a Sefer Torah rests;

Question: A case occurred in which R. Elazar realized that he was sitting on a bed on which a Sefer Torah rests. He sat on the floor and was grieved like one bitten by a snake!

Answer: That is wrong. Really, he realized that the Sefer Torah was on the floor!

(Rav Yehudah): If a Sefer Torah was written like an Igeres (letter, i.e. he was not precise about extra or missing letters; Rashi - alternatively, it was without Sirtut), it is Pasul.

Question: What is the reason?

Answer: We learn a Gezerah Shavah "Kesivah-Kesivah" from Sefer (Torah; alternatively, from Sefer Kerisus (Get); Tosfos - from Megilas Sotah).

(Rav Yehudah): If one hung a Mezuzah from a stick, it is Pasul.

Question: What is the reason?

Answer: It must be 'bi'Sh'arecha' (on your gates).

Support (Beraisa): If one hung a Mezuzah from a stick or affixed it in back of the door, this is dangerous (Tosfos - one might bang his head on it; Rashi - he is not guarded from Mazikim, because) he does not fulfill the Mitzvah.

The household of Melech Munvaz would take Mezuzos with them when they traveled. They would hang a Mezuzah in the doorway of the inn (even though they were exempt), to commemorate the Mitzvah.

(Rav Yehudah): The Mezuzah should be affixed in the width of the entrance.

Objection: This is obvious. It says "uvi'Sh'arecha"!

Answer: Rava taught that the Mezuzah should be affixed in the Tefach closest to Reshus ha'Rabim;

One might have thought that the further from the house the better, so it should be entirely outside the entranceway. Rav Yehudah teaches that this is not so.