- External structural requirements of תפלין, from הלכה למשה מסיני (ex. תיתורא)
Rav says the "תיתורא" of tefillin was taught as a הלכה למשה מסיני. This refers to the extended fourth wall of the tefillin, which is folded underneath to close the compartments (called "תיתורא" – bridge because it resembles a plank). Abaye says a הלכה למשה מסיני requires the "מעברתא" of tefillin, i.e., the back extension of the תיתורא, through which the strap “passes” back and forth. Abaye said a הלכה למשה מסיני requires the "שי"ן" of tefillin (the creases made on the outer sides of the תפלין של ראש resembling the letter shin). וצריך שיגיע חריץ למקום התפר – And the groove between each compartment must reach the place for the stitching at the bottom. However, Rav Dimi said that as long as the grooves are recognizable on top, they need not reach the base. Later, a Baraisa adds that a הלכה למשה מסיני requires תפלין to be מרובעות – square. Rav Pappa says this means בתפרן – in their stitching (i.e., he should not pull the stitch too tight, causing the leather base to contract and no longer be square), ובאלכסונן – and in their diagonal (i.e., the length and width should be equal, so that the diagonal matches that of a proper square).
- Requirements of the רצועות (color, length)
Rebbe Yitzchak says that a הלכה למשה סיני requires the רצועות – straps of the tefillin to be black. This is challenged from a Baraisa teaching that the רצועות must be במינן – with their type of material (i.e., leather), and can be dyed green, black, or white!? [However, they may not be red, because it disgraces the wearer, who will seem to have bleeding scabs, or had relations with his wife while she was a נדה.] The Gemara answers: כאן מבפנים – [the Baraisa] allows various colors for the inside of the straps, whereas כאן מבחוץ – [Rebbe Yitzchak] required black for the outside of the straps. Even the inside coloring can cause disgrace to the wearer, because זימנין דמתהפכין ליה – occasionally they turn over, and their color is visible. Later, the Gemara proves that רצועות have a minimum shiur in length beyond the knot. Reish Lakish says it is עד אצבע צרדה – until the index finger. Rav Kahana demonstrated this as כפוף – curved, i.e., the space between one’s index and middle finger spread apart. Rav Ashi demonstrated this as פשוט – straight, i.e., the index finger and thumb spread apart. The Gemara records practices of Amoraim whose רצועות were too long: Rabbah hung them behind his back, Rav Acha bar Yaakov braided them, and Rabbah brei d’Rabbana, hung them in front of himself, as we do.
- קשר של תפלין (וראו כל עמי הארץ)
Rav was quoted as saying that a הלכה למשה מסיני teaches the requirements of קשר של תפלין – the tefillin knot, which together form the letters ש, ד, and י. The shin is embossed on the של ראש, the knot of the של ראש is tied into a daled, and the small knot attaching the של יד forms a yud. Rav Nachman adds: ונוייהן לבר – and their beauty must face outward, referring to the letters forming the name שקי, or the side of the רצועות dyed black. The passuk says: וראו כל עמי הארץ כי שם ה' נקרא עליך ויראו ממך – and all the nations of the world will see that Hashem’s Name is proclaimed over you, and they will be in awe of you. Rebbe Eliezer says this refers to the תפלין של ראש. Rebbe Shimon Chasida says that when Hashem told Moshe he would see “Hashem’s back,” it means the קשר של תפלין at the back of His head. Rav Yehudah says the קשר must be למעלה – above, on the back of the head, כדי שיהו ישראל למעלה ולא למטה – to symbolize that Yisroel should be above and not below. It must be כלפי פנים – opposite his face, i.e., centered, כדי שיהו ישראל לפנים ולא לאחור – to symbolize that Yisroel should be in the front, and not the back.