Rabbenu Tam Tefillin
Jewish men wear at least one pair of Tefillin every weekday. Both Tefillin Shel Rosh and Shel Yad contain four biblical passages (parshiot), the order of which is disputed primarily by Rashi and his grandson Rabbenu Tam, resulting in "Rashi Tefillin" and "Rabbenu Tam Tefillin," each one written with the parshiot according to one of the two views. Due to the unresolved nature of the debate, the pious practice developed to wear each pair of Tefillin every day, in order to fulfill both opinions. There are also additional types of Tefillin, known as "Shimusha Rabba Tefillin" and "Ra'avad Tefillin that are worn by people of outstandingly pious nature.
Arrangement of Paragraphs (Seder HaParshiot)
|Rashi||Kadesh Li||Vehaya Ki||Shema||Vehaya Im|
|Rabbeinu Tam||Kadesh Li||Vehaya Ki||Vehaya Im||Shema|
|Shimusha Rabba||Vehaya Im||Shema||Vehaya Ki||Kadesh Li|
|Ra'avad||Shema||Vehaya Im||Vehaya Ki||Kadesh Li|
- There is much discussion among the Rishonim (early authorities) about the order in which the biblical passages should be written in the arm and head Tefillin. The rabbis most famous for this dispute were Rashi and his grandson Rabbenu Tam. Rashi held that the order is: Kadesh Li (Shemot 13:1-10), VeHaya Ki Yeviehcha (Shemot 13:11-16), Shema (Devarim 6:4-9), VeHaya Im Shemoa (Devarim 11:13-21). Rabbenu Tam held that the last two passages were switched (thus making the following order Kadesh Li, VeHaya Ki Yeviehcha, VeHaya Im Shemoa, Shema). The custom of the world is to follow Rashi's opinion. 
- Some say that Shimusha Rabba and Raavad are only different from Rashi and Rabbenu Tam in the Shel Rosh, but they are exactly the same in the Shel Yad.
Due to the unresolved nature of the dispute between Rashi and Rabbenu Tam as to how to order the Parshiot, Shulchan Aruch (Orach Chaim 34:2) recommends that a God-fearing person wear both to satisify both opinions. As we do not know which is correct and which is not, one should have in mind/stipulate that "if Rashi's view is the truth (Emet), then the Rashi Tefillin should count as Tefillin and the Rabbeinu Tam ones should be retzuot be'alma (mere straps), and "if Rabbenu Tam's view is the Emet, then the Rabbeinu Tam Tefillin should count as Tefillin and the Rashi ones should be retzuot be'alma to avoid violating the prohibition of Bal Tosif. At the same time, from a Kabbalistic perspective, there is actually no dispute at all, and they are, in fact, both Emet and mandated by the Torah. Accordingly, the stipulation should be modified with an additional clause that "If the Kabbalah is true, then they should both count as Tefillin." Nevertheless, this modification is decried as a violation of "Bal Tosif" by those who are not as taken by this view.
Who Should Wear Rabbenu Tam Tefillin?
- Originally, primarily pious individuals had the practice of wearing both Tefillin of Rashi and Rabbenu Tam, and it would be haughty for a common person to attempt to mimic their practices. Nowadays, it is very common for people of a variety of levels of spiritual stature to wear them, so the issue of looking haughty or arrogant (yuhara) no longer applies.
- In general, unmarried individuals should not wear Tefillin of Rabbenu Tam unless they know that they are capable of having pure thoughts for as long as they are wearing Tefillin. The custom of Chabad Chassidim is for every boy to wear them from the age of Bar Mitzvah, including the preparation time before his Bar Mitzvah.
- Some say that a person should wear Rabbenu Tam tefillin at least once in their life.
- A mourner should wear Rabbenu Tam Tefillin even during Shiva. The same is true for everybody on Tisha be'Av.
When to Wear Rabbenu Tam Tefillin
- One generally puts on the Rabbenu Tam Tefillin after praying Shacharit with Rashi Tefillin, before Ashrei or Uva Letzion.
- On Rosh Chodesh, one should put on Rabbenu Tam Tefillin before Keriat HaTorah, even during Berich Shemeh, and recite the two Parshiot of Shema and Vehaya. On should ideally not put them on after Mussaf to learn Torah even if he usually does. However, if he's the Shaliach Tzibbur and has no previous opportunity or prays very slowly and won't be able to finish Shema in time for Mussaf, he may put them on afterwards. Alternatively, there is no reason not to put them on before Shacharit, if that is more feasible.
- On Purim, some make sure to have their Rabbenu Tam Tefillin on for the Megillah reading, but afterwards is fine, too.
- See When_to_Wear_Tefillin for more general details and regarding the week of mourning (Avelut).
How to Wear Rabbeinu Tam Tefillin
- Although no Beracha is recited on Rabbeinu Tam Tefillin, one should not speak between putting on the shel yad and the shel rosh. He may, however, answer Amen to Kaddish, Kedusha, and Berachot, but not Baruch Hu uVaruch Shemo to Hashem's name, but one should not put them on during or right before Kaddish or Kedusha in the first place. Note how some argue one may not answer at all. To avoid this issue further, one should not switch them during Chazarat HaShatz.
- If one mistakenly put on Rabbenu Tam first with a Beracha, he should take them off and switch to Rashi Tefillin. Some poskim say one should recite a new Beacha when putting on the Rashi Tefillin,, but others say a new Beracha would only be warranted if one interrupted by praying or speaking in between the original Beracha and Rashi Tefilln.
- One should intend to fulfill the mitzvah as discussed above ("The Truth").
- One need not be concerned for Lo Titgodedu when wearing Rabenu Tam Tefillin in a place where nobody else does, and he may put them on after Ashrei or at home instead.
- While reciting Shema with Rabbenu Tam Tefillin, one may respond to someone out of awe or honor and Amen to Kaddish, Kedusha, and Berachot. He must only be vigilant not to speak mundane speech.
- The Rashi and Rabbenu Tam Tefillin should be placed in separate bags.
Rashi and Rabbenu Tam at The Same Time
- The Gemara states how there is room on the head for two pairs of Tefillin; therefore, some say one should ideally wear both Rashi and Rabbenu Tam at the same time, one in front of the other. Since this is only possible if one has Tefillin that are small enough to fit in the appropriate spaces on one's body and ensures that the parshiot were prepared and inserted by an expert sofer, many recommend just wearing them consecutively. If nobody else in the synagogue wears both at the same time, it's also better to wear them consecutively.
- If one attempts to wear them both at the same time, he should make sure the boxes and knots of the Shel Roshs do not overlap, but it's fine if the straps overlap.
- Some Poskim give lenient dispensation regarding how high up on the arm one can place the Rashi Tefillin when attempting to wear both pairs simultaneously, but others argue that if there isn't enough room to wear them both in the ideal fashion, they should just be worn consecutively instead.
- Ten Minute Halacha: Rabeinu Tam Tefillin by Rabbi Aryeh Lebowitz
- Order of Parshiyos in Tfillin: Rashi and Rabbeinu Tam by Rabbi Zvi Sobolofsky
- Shulchan Aruch O.C. 34:1, Halacha Brurah 34:1, Kitzur Shulchan Aruch of Rav Rephael Baruch Toledano, siman 10, miscellaneous laws (of tefillin), seif 2. Shut Min HaShamayim 3 says that the debate between Rashi and Rabbeinu Tam is also a debate in Heaven. See Rav Reuven Margaliot's notes ad loc. where he presents an exposition demonstrating how the debate between Rashi and Rabbeinu Tam precedes them to the times of the Tannaim and the Rishonim are only debating which view is accepted as Halacha. According to the Arizal, there's no machloket: both Rashi and Rabbeinu Tam are true. (Or LeTzion 2:3:8)
- Piskei Teshuvot 34:1
- Shulchan Aruch (Orach Chaim 34:2)
- Ohr LeTzion 2:3:8
- Yabia Omer vol. 9 OC 108:21. See Yalkut Yosef (Orach Chaim 34:1) at length in the footnotes
- Kitzur Shulchan Aruch of Rav Rephael Baruch Toledano, siman 10, the order of the donning, seif 2. Shulchan Aruch 34:2-3 rules that that the especially pious should wear both sets but adds that only one commonly known to be especially pious may do so, so as not to appear as arrogant in one's piety. However, many Acharonim write that since it has become the practice of many common people to wear both Tefillin of Rashi and Rabbenu Tam it is not considered an issue of arrogance to wear both pairs of Tefillin. See Aruch Hashulchan 34:5, Or LeTzion 2:3:8, 11, Yalkut Yosef (Orach Chaim 34:3), Halacha Brurah (Rabbi David Yosef, 34:1), Piskei Teshuvot 34:2 for more sources. Sh"t Yabia Omer OC 3:4 writes that if one has this stringency he should remove the Rashi and place the Rabbeinu Tam before the kedusha of "uva litzion".
- Aruch Hashulchan 34:5 writes that since in some countries it is common to wear them it isn’t yuhara anymore. Rav Schachter ( Halachipedia Article 5780) agrees with the Aruch Hashulchan. Rav Ovadia Yosef (Yabia Omer OC 1:3:6, Halacha Brurah 34:1) similarly holds that once the world was exposed to the Arizal’s torah who bolstered the importance of Rabbenu Tam tefillin it isn’t yuhara anywhere. Additionally, some poskim say that it is only an issue of yuhara if one wears both simultaneously.
- In Morocco, very few people wore Rabbenu Tam Tefillin, and even those who did did so privately. Nevertheless, nowadays that it is more commonplace for even common people to wear them, Rav Mordechai Lebhar (Magen Avot, Orach Chaim 34:2 reports that Rav Elyashiv, Rav Meshash, and Mav Shternbuch think it is fine for one to wear them and not be concerned or Yuhara. See Shemesh uMagen 3:58:4 and Mikveh Hamayim 6:6.
- Halacha Brurah 34:2. Chacham Ben-zion Abba Shaul Sh"t Or Letzion 2:13:11 also writes that Sephardim should only wear Rabbenu Tam Tefillin after marriage. Divrei Yatziv 42 and Mishneh Halachot 6:12 agree
- Shaarei Halacha uMinhag Orach Chaim 1:29, The Tefillin of Rabbeinu Tam. See Likutei Sichos Purim 5736, Motza'ei Va'eira 5739, and Pekudei 5741.
- Aruch Hashulchan 34:5 writes that since it is common to wear them in some places it isn't yuhara and praiseworthy is one who wears them. Iggerot Moshe OC 4:9 writes that since he had particular concerns of whether they were kosher he didn't wear Rabbenu Tam tefillin. Dirshu 34:24 cites Dinim Vhanhagot 3:15 of the Chazon Ish that he didn't wear Rabbenu Tam tefillin. However, the Chafetz Chaim and the Steipler (Meir Oz tefillin p. 481) held that a person should wear them once in his life.
- Or LeTzion 2:3:8, Yabia Omer vol. 9 OC 108:21
- Yalkut Yosef (Orach Chaim 34:9)
- Yalkut Yosef (Orach Chaim 34:17)
- Shulchan Aruch (Orach Chaim 34:2)
- Kaf HaChaim (Orach Chaim 25:52)
- Shu"t Yabia Omer 3:3, 9 OC 108:27, Yalkut Yosef (Orach Chaim 34:5)
- Or Letzion 2:3:10
- Rav Pe'alim 3:2:2
- Yalkut Yosef (Orach Chaim 34:7)
- Ben Ish Chai Vayera 24
- Rav Ovadia Yosef in Halichot Olam volume 1 page 26 says that this is only if the person has prayed something in between but if he remembers immediately no bracha should be recited. Yalkut Yosef (Orach Chaim 34:11)
- Yalkut Yosef (Orach Chaim 34:1, 8)
- Yalkut Yosef (Orach Chaim 34:14, 15)
- Because one of them is absolutely kodesh and the other not. Shulchan Aruch (Orach Chaim 34:4), Kitzur Shulchan Aruch of Rav Rephael Baruch Toledano, siman 10, the order of the donning, seif 5, Yalkut Yosef (Orach Chaim 34:18)
- Or LeTzion 2:3:8, Yabia Omer vol. 9 OC 108:21, Yalkut Yosef (Orach Chaim 34:2), Piskei Teshuvot 34:2. See Yaskil Avdi O.C. 8:22, Yabia Omer vol. 1 OC 3
- Ohr LeTzion 2:3:9, Yabia Omer 9 OC 108:26, Yalkut Yosef (Orach Chaim 34:4). See Yabia Omer 5 OC 5, Halichot Olam 1 pg 24
- Or LeTzion 2:3:2
- Yabia Omer vol. 9 OC 108:21