Menachos Daf 34 מנחוס דַף 34

Rav Pappa visited the home of Mar Shmuel, and saw that his entrance had only פצים אחד – one sidepost, which was on the left side of the entrance, and it had a mezuzah. Rav Pappa challenged Mar Shmuel that although Rebbe Meir (cited below) holds that an entrance with a single sidepost requires a mezuzah, that is only when the sidepost is on the right side of the entrance, not on the left!? This is based on a Baraisa which darshens "ביתך" – your house to mean the right side, as Rabbah explains: דרך ביאתך מן הימין – the way of your entering, which is the right side, דכי עקר איניש כרעיה דימינא עקר [ברישא] – because when a person begins to move, it is his right foot which he moves first. Another source is brought from a passuk describing a chest for donations placed on the right side of the עזרה’s main entrance. In a Baraisa, Rebbe Meir says that a house which has only one sidepost requires a mezuzah, while the Rabbonon say it does not. The Rabbonon say the plural "מזוזות" – doorposts requires two doorposts, and Tannaim give two explanations of Rebbe Meir’s position.

A Baraisa states that the תפלין של ראש are made of four בתים – compartments made of a single hide. The פרשיות are written on four separate hides, but if they were written on one and were inserted into the four compartments, they are valid. If they are written on one hide, Rebbe says a space must be left between the פרשיות, but the Chochomim say it is unnecessary. All agree, however, that a string or cord must be inserted between each compartment. It concludes: ואם אין חריצן ניכר – and if their grooves (external lines indicating the separate compartments) are not recognizable, the tefillin are invalid. Another Baraisa describes the תפלין של יד: the פרשיות are written onto a single hide, but if they were written on four separate hides, it is valid. Rebbe Yehudah says they must be attached, but Rebbe Yose says it is unnecessary. Rebbe Yose says Rebbe Yehudah conceded that תפלין של ראש may be used as תפלין של יד by draping a hide over them, because Rebbe Yehudah retracted his opinion. The Gemara adds that only unused תפלין של ראש can be used as תפלין של יד.

A Baraisa teaches: כיצד סדרן – what is the order [of the four פרשיות of tefillin]? The פרשיות of "קדש לי" and "והי' כי יביאך" are מימין – placed on the right side, and the פרשיות of "שמע" and "והיה אם שמוע" are משמאל – placed on the left side. The Gemara objects that another Baraisa says the opposite, and Abaye answers: כאן מימינו של קורא – here (the first Baraisa) refers to the right side of someone reading the פרשיות (i.e., facing the wearer), כאן מימינו של מניח – whereas here (the second Baraisa) refers to the right side of the wearer. והקורא קורא כסדרן – And the reader (who faces the wearer) reads the פרשיות according to their order in the Torah (i.e., from right to left, קדש, then והיה כי יביאך, then שמע, then והיה אם שמוע). [This is the order according to Rashi, and is how “Rashi tefillin” are made. Rabbeinu Tam reverses the order of the last two פרשיות, so that שמע is in the leftmost chamber (and the two "והיה" parshiyos are side-by-side), and is the order used in “Rabbeinu Tam tefillin.”] Rav says: החליף פרשיותיה פסולות – if one changed the order of the פרשיות, they are invalid.