ת"ר לטטפת לטטפת לטוטפת הרי כאן ד' דברי רבי ישמעאל
§ The Sages taught in a baraita: With regard to the number of compartments in the phylacteries of the head, the verse states: “It shall be for a sign upon your hand, and for totafot between your eyes” (Exodus 13:16), with the word totafot spelled deficient, without a vav before the final letter, in a way that can be read as singular; and again: “They shall be for totafot between your eyes” (Deuteronomy 6:8), spelled as a singular word; and again: “They shall be for totafot between your eyes” (Deuteronomy 11:18), this time spelled plene, with a vav before the final letter, in a manner that must be plural. There are four mentions of totafot here, as the third one is written in the plural and therefore counts as two. Consequently, it is derived that the phylacteries of the head must have four compartments. This is the statement of Rabbi Yishmael.
ר"ע אומר אינו צריך טט בכתפי שתים פת באפריקי שתים
Rabbi Akiva says: There is no need for this proof, as the requirement of four compartments can be derived from the word totafot itself: The word tot in the language of Katfei means two, and the word pat in the language of Afriki also means two, and therefore totafot can be understood as a compound word meaning four.
ת"ר יכול יכתבם על ד' עורות ויניחם בד' בתים בד' עורות ת"ל (שמות יג, ט) ולזכרון בין עיניך זכרון אחד אמרתי לך ולא ב' וג' זכרונות הא כיצד כותבן על ד' עורות ומניחן בד' בתים בעור אחד
The Sages taught in a baraita: One might have thought that a scribe should write the passages of the phylacteries of the head on four separate hides, i.e., parchments, and place them in four compartments of four hides, one passage in each compartment. Therefore, the verse states: “And for a memorial between your eyes” (Exodus 13:9). This teaches: I said to you that the phylacteries are one memorial, but not that they are two or three memorials, i.e., the phylacteries themselves must be one unit. How so? One writes the passages on four hides and places them in four compartments fashioned of one hide.
ואם כתבן בעור אחד והניחן בד' בתים יצא וצריך שיהא ריוח ביניהן דברי רבי וחכ"א אינו צריך ושוין שנותן חוט או משיחה בין כל אחת ואחת ואם אין חריצן ניכר פסולות
And if a scribe wrote all four of them on one hide and placed them in four compartments by slitting the parchment between each of the passages, one who dons these phylacteries has fulfilled his obligation. And in such a case it is necessary for there to be a space between each of the passages, so that each can be placed in a separate compartment; this is the statement of Rabbi Yehuda HaNasi. And the Rabbis say: It is not necessary for there to be a space between them. And Rabbi Yehuda HaNasi and the Rabbis agree that one places a string or a thicker band between each and every one of the four compartments. The baraita adds: And if their furrows, i.e., the lines marking the separation between the compartments, are not noticeable from the outside, the phylacteries are unfit.
תנו רבנן כיצד כותבן תפלה של יד כותבה על עור אחד ואם כתבה בארבע עורות והניחה בבית אחד יצא וצריך לדבק שנאמר (שמות יג, ט) והיה לך לאות על ידך כשם שאות אחת מבחוץ כך אות אחת מבפנים דברי ר' יהודה ר' יוסי אומר אינו צריך
The Sages taught in a baraita: How does a scribe write them? With regard to the phylacteries of the arm, he writes it on one hide. But if he wrote it on four separate hides and placed it in one compartment, one who wears it has fulfilled his obligation. And in such a case it is necessary to attach the four parchments, as it is stated: “And it shall be for a sign for you upon your arm” (Exodus 13:9). This teaches that just as the phylacteries of the arm are one sign on the outside, as the compartment is fashioned from a single hide, so too, they must be one sign on the inside, i.e., the four passages must be on a single parchment. This is the statement of Rabbi Yehuda. Rabbi Yosei says: It is not necessary to attach the passages.
א"ר יוסי ומודה לי ר' יהודה ברבי שאם אין לו תפילין של יד ויש לו שתי תפילין של ראש שטולה עור על אחת מהן ומניחה מודה היינו פלוגתייהו אמר רבא מדבריו של ר' יוסי חזר בו ר' יהודה
Rabbi Yosei says: And Rabbi Yehuda the Distinguished [Beribbi] concedes to me that if one does not have phylacteries of the arm but has two phylacteries of the head, that he covers one of them with patches of hide, to render it like one compartment, and places it on his arm. The Gemara asks: How can Rabbi Yosei say that Rabbi Yehuda concedes to him in this case? This is the very situation in which their dispute applies, as they disagree over whether or not the passages of the phylacteries of the arm may be written on separate parchments. Rava said: From Rabbi Yosei’s statement one can infer that Rabbi Yehuda retracted his opinion and accepted Rabbi Yosei’s ruling.
איני והא שלח רב חנניה משמיה דר' יוחנן תפלה של יד עושין אותה של ראש ושל ראש אין עושין אותה של יד לפי שאין מורידין מקדושה חמור' לקדושה קלה
Rabbi Yosei said that all agree that one can convert phylacteries of the head into phylacteries of the arm. The Gemara asks: Is that so? But Rav Ḥananya sent the following ruling in the name of Rabbi Yoḥanan: If one has phylacteries of the arm, he can convert it to phylacteries of the head, but if one has phylacteries of the head, he cannot convert it to phylacteries of the arm, because one does not reduce the sanctity of an item from a level of greater sanctity of phylacteries of the head to a level of lesser sanctity of phylacteries of the arm.
ל"ק הא בעתיקתא הא בחדתתא ולמ"ד הזמנה מילתא היא דאתני עלייהו מעיקרא
The Gemara answers: This is not difficult, as this ruling is stated with regard to old phylacteries, which have already been worn on one’s head and therefore have a greater level of sanctity, whereas that ruling is stated with regard to new phylacteries, which have not yet been used. The Gemara adds: And according to the one who says that designation is significant, i.e., once one designates an item for use in fulfilling a particular mitzva, it assumes the sanctity of an item used for mitzvot, this ruling is stated with regard to a case where he stipulated with regard to them from the outset that he may convert it from phylacteries of the head to phylacteries of the arm, and only in this circumstance it is permitted to convert them.
ת"ר כיצד סדרן קדש לי והי' כי יביאך מימין שמע והי' אם שמוע משמאל
§ The Sages taught in a baraita: How does one arrange the four passages inside the phylacteries? The passage of: “Sanctify unto Me” (Exodus 13:1–10), and the passage of: “And it shall be when He shall bring you” (Exodus 13:11–16), are placed on the right; the passage of: “Listen, O Israel” (Deuteronomy 6:4–9), and the passage of: “And it shall come to pass, if you shall hearken diligently” (Deuteronomy 11:13–21), are placed on the left.
והתניא איפכא אמר אביי ל"ק כאן מימינו של קורא כאן מימינו של מניח והקורא קורא כסדרן:
The Gemara asks: But isn’t it taught in a baraita that one places them in the opposite manner, with the first two passages on the left and the latter two on the right? Abaye said that it is not difficult: Here it means to the right of the reader, i.e., one who is standing opposite the one donning the phylacteries, whereas there it means to the right of the one who is donning the phylacteries. And in this manner the reader reads the passages in their order, as they appear in the Torah, starting with Exodus 13:1–10 to his right.
אמר רב חננאל אמר רב החליף פרשיותיה פסולות אמר אביי לא אמרן
Rav Ḥananel says that Rav says: If one exchanged its passages, i.e., placed them in a different order within the compartment, the phylacteries are unfit. Abaye said: We did not say this