Gemara

(Mishnah): 'All are obligated in the Mitzvah of Tzitzis.'

Kidushin 29a (Mishnah): Women are exempt from a Mitzvas Aseh sheha'Zman Gerama (positive Mitzvah that only applies at certain times).

33b (Beraisa): The following Mitzvos are Zman Grama: Sukah, Lulav, Shofar, Tzitzis and Tefilin;

Menachos 43a (Beraisa): All are commanded about Tzitzis - Kohanim, Leviyim and Yisraelim, converts, women and slaves;

R. Shimon exempts women (and slaves), for Tzitzis is Zman Grama. Women are exempt from all such Mitzvos.

Question: Why does R. Shimon exempt women?

Answer (Beraisa): "U'Re'isim Oso" excludes a night garment.

Shabbos 25b: R. Yehudah's Talmidim hid the corners of their (linen) garments (they did not have Tzitzis).

R. Yehudah: I taught to you that Beis Shamai exempt linen garments from Tzitzis and Beis Hillel obligate, and the Halachah follows Beis Hillel!

His Talmidim held that Chachamim decreed to exempt linen garments, due to a night garment (even according to Beis Hillel).

27b (R. Acha brei d'Rava): Tana d'Vei R. Yishmael includes other garments regarding Tum'ah because it says "Oh Veged";

Question: We should include other garments also regarding Tzitzis - it says "Asher Techaseh Bah"!

Answer (Rav Ashi): That comes to include the garment of a blind man.

Zevachim 18b (Beraisa #1): "Al Arba Kanfos Kesusecha" excludes a three-cornered garment from Tzitzis.

(Beraisa #2): "Al Arba Kanfos Kesusecha" excludes a three or five-cornered garment from Tzitzis.

The first Tana expounds "Asher Techaseh Bah" to obligate a five-cornered garment. The second Tana uses it to obligate a blind person's garment;

(Beraisa): "Asher Techaseh Bah" includes a blind person's garment. Therefore, "u'Re'isem Oso" excludes a night garment.

The first Tana learns this from "Asher". The second Tana does not expound "Asher".

Berachos 13a (Mishnah): We say v'Hayah Im Shamo'a before va'Yomer, because the former (discusses learning Torah, which) applies during the day and night, whereas va'Yomer (discusses Tzitzis, which) applies only during the day.

14b - Rav Yosef: The following is a wonderful teaching!

(Shmuel bar Yehudah): In Eretz Yisrael, in the evening they say "Daber El Bnei Yisrael v'Amarta Aleihem," and then, "Ani Hash-m Elokeichem Emes."

Question (Abaye): Why do you praise it? Rav Kahana taught that one should not begin (the third Parshah). If one began, he should finish it!

R. Yitzchak taught that "Daber El Bnei Yisrael" is not considered beginning the Parshah, but "v'Amarta Aleihem" is!

Answer (Rav Papa): In Eretz Yisrael, they hold that even "v'Amarta Aleihem" is not considered beginning, until one says "v'Asu Lahem Tzitzis."

(Abaye): Since they begin the Parshah, we (in Bavel) also begin. We consider "v'Amarta Aleihem" like beginning the Parshah, so we finish it, as Rav Kahana taught.

Eruvin 96a: The Tana'im agree that one does not need intent to fulfil Mitzvos. They argue about whether intent is required to transgress 'Bal Tosif' (adding to Mitzvos).

(Beraisa): Michal (Sha'ul's daughter) wore Tefilin, and the wife of Yonah (the Navi) was Olah l'Regel (came to Yerushalayim for the festivals). Chachamim did not protest against either of them.

Inference: They did not protest against Michal because they held that Tefilin is Lo ha'Zeman Gerama.

Rejection: Perhaps the Tana holds like R. Yosi, who says Nashim Somchos Reshus! (Women may press on a Korban, even though they are exempt.)

Rishonim

Rif and Rosh (Hilchos Tzitzis 11a and 1): The Halachah follows R. Shimon, who exempts women from Tzitzis.

Rambam (Hilchos Tzitzis 3:7): We decree not to put Techeiles on a linen garment, lest one wear it at night, which is not Zman Tzitzis, and he transgresses Sha'atnez when there is no Mitzvas Aseh.

Rambam (9): A woman is exempt from Tzitzis. If she wants to wear Tzitzis without a Berachah, she may.

Ra'avad: If the Tzitzis contains Sha'atnez, she is forbidden. Some say that she has Reshus to bless.

Hagahos Maimoniyos (30): The Bavli says that Chachamim did not object to women who performed Mitzvos such as Tefilin and Aliyah l'Regel. The Yerushalmi says that Chachamim objected. I heard that we protest only where there is concern for transgression, such as Chulin ba'Azarah, Ervah (if a married woman's hair shows), or blowing a Shofar on Rosh Hashanah. Where there is no concern, such as Sukah and Lulav, we do not protest.

Rosh (ibid.): R. Tam proved that the Halachah follows R. Shimon. R. Yehudah's Talmidim hid the corners of their linen garments. They held that Chachamim decreed not to put Tzitzis (woolen Techeiles) on them, lest one do so on a night garment, and it is exempt, like R. Shimon. This is Sha'atnez without a Mitzvah (to override it). Since the Gemara chose this reason, and not the other reason given in Menachos (lest one use imitation Techeiles, or lest the garment tear and become exempt), this shows that the Halachah follows R. Shimon. Also, we asked that just like we include other garments regarding Tum'ah, we should them also for Tzitzis, from "Asher Techaseh Bah." We answered that the verse includes the garment of a blind man. This is like R. Shimon, who does not use the verse to include a five-cornered garment. Also, a Stam Beraisa in Kidushin (33b) counts Tzitzis among Mitzvos Aseh sheha'Zeman Gerama. Also, Tana'im argue in Zevachim 18b. One includes the garment of a blind man from Asher Techaseh, and the other learns from Asher. We do not say that one Tana holds like Rabanan. Rather, we strain to establish both like R. Shimon. Also, we say v'Hayah Im Shamo'a before va'Yomer, because va'Yomer applies only during the day. In Eretz Yisrael, Tanai they would begin Parshas Tzitzis, and skip the Mitzvah of Tzitzis, for it does not apply at night. Abaye said that since they begin, in Bavel also we begin. We consider "v'Amarta Aleihem" like beginning the Parshah, so we finish it, like Rav Kahana taught. This shows that all the Amora'im hold that letter of the law, one should not say it at night. We do not hold like Rav Yehudah, who put Techeiles on his wife's garment (Menachos 43a).

Tosfos (Menachos 40b DH Mishum): R. Tam says that even though a night garment is exempt even during the day, and day garments are obligated even at night, Tzitzis is considered Zeman Gerama, because the day causes the garment to be obligated. However, the Yerushalmi says that Rabanan hold that Tzitzis is not Zeman Gerama because it applies to a garment used for day and night.

Gra (OC 17:2): Based on the Yerushalmi, the proofs that the Halachah follows R. Shimon are invalid, for even Chachamim exempt a night garment. However, the Bavli disagrees. It holds that only R. Shimon exempts women.

Ran (Kidushin 14b DH Eizo): Some texts of the Beraisa (Kidushin 33b) omit Tzitzis, for our Tana holds that Tzitzis applies even at night, and women are obligated because it is not Zman Grama. Other texts include Tzitzis. Our Tana is R. Shimon. Mar Amram Chasida put Techeiles on his wife's garments. This was Midas Chasidus. This is why he did so, but most Chachamim did not.

Question: Why is Tzitzis considered Zman Grama? A night garment is exempt even during the day. If not, Chachamim would not exempt a Sadin from Tzitzis, for it is sometimes worn during the day. (Since "U'Re'isim Oso" excludes night garments,) it follows that day garments are obligated even at night. If so, there is no garment that is obligated only at certain times!

Answer #1 (Ran, ibid.): Also a day garment is exempt at night. The only garment that is obligated is a day garment, during the day.

Answer #2 (Tosfos Kidushin 34a DH Tefilin): Tzitzis is considered Zman Grama because the time we wear the garment determines whether or not it is obligated.

Question: The Mitzvah of Tzitzis is written right after the Isur of Kilayim, to teach that these Mitzvos apply to the same people. Just like women are forbidden to wear Sha'atnez, they should be commanded about Tzitzis!

Answer (Ran, ibid.): We already use the Semichus to permit Sha'atnez for the Mitzvah of Tzitzis, therefore we do not learn another law from it which opposes the general rule that women are exempt from Mitzvos Aseh sheha'Zman Grama. The verses themselves suggest that we expound the first way. "Do not wear Sha'atnez...; Make for yourself Gedilim" - even though Sha'atnez is forbidden, it is permitted for Tzitzis.

Tosfos (Eruvin 86a DH Michal): Rashi says that if it were Zeman Gerama, Chachamim would have protested due to Bal Tosif. The Ri disagrees. R. Yehudah holds that Ein Nashim Somchos Reshus, and he holds that Hilni ha'Malkah used to sit in a Sukah with her sons (Sukah 2b)! However, perhaps she sat due to her sons, so it does not look like Bal Tosif. Alternatively, Rava holds that not at the time of the Mitzvah, one transgresses Bal Tosif only with intent. A woman is exempt, so it is considered not at the time of the Mitzvah. However, this is difficult. Rather, the one who holds that it is Zeman Gerama forbids women because they are not careful enough to have a clean body like Tefilin requires. Olas Re'iyah looks like Chulin ba'Azarah, or entering the Azharah without need. Blowing a Shofar is a Melachah mid'Rabanan.

Ran (Rosh Hashanah 9b DH ul'Inyan Halachah): We learn from Michal and Yonah's wife that women may blow Shofar. We are not concerned for Shevus or Bal Tosif.

Poskim

Shulchan Aruch (17:2): A woman is exempt from Tzitzis because it is Mitzvas Aseh sheha'Zman Gerama.

Rema: If she wants to cover herself (with a Talis) and bless, she may, just like any Aseh sheha'Zman Gerama.

Magen Avraham (1): Even one who is not commanded and fulfills, gets reward. They can say (bless) 'that (Hash-m) commanded us', because men are commanded, and also women receive reward.

Eshel Avraham: Bal Tosif does not apply to women, because men are commanded, and woman was taken from man.

Maharsha (Rosh Hashanah 33a DH b'Ferush Rashi): Rashi says that if women blow the Shofar, Bal Tosif applies. This is difficult. Bal Tosif is only when one does a Mitzvah, and adds to it. Rashi should have said that it is an Isur mid'Rabanan for women to blow since it is not a Mitzvah. R. Yehudah forbids women to do Semichah due to Avodah with Kodshim, but not due to Bal Tosif!

Pnei Yehoshua 33a DH b'Ferush Rashi: The Maharsha overlooked Eruvin 96a. The Gemara connotes that according to the opinion that Nashim Somchos Reshus, Bal Tosif does not apply to women. Rashi explains like this there. Tosfos explains like the Maharsha, but this is not difficult for Rashi. Tosfos concluded that Bal Tosif does not apply to women because we hold like Rava, that one transgresses only (with intent or) at the time of the Mitzvah. Abaye disagrees. Therefore, in our Sugya, surely Abaye holds that if Ein Nashim Somchos Reshus, they transgress Bal Tosif!

Pri Megadim (Petichah Klalis, 1:40): Rashi and Tosfos said that it looks like Bal Tosif. This is only mid'Rabanan. When women fulfill an Aseh sheha'Zeman Gerama, they should intend for a Mitzvah mid'Rabanan. I.e. they are exempt, and they are stringent on themselves.

Rema (ibid.): However, this looks like haughtiness. Therefore, she should not wear Tzitzis, since it is not an obligation on the person. I.e. one need not buy a (four-cornered) garment to become obligated.

Beis Yosef (DH Kosav): The Agur says that it is folly for women to wear Tzitzis, and it looks like haughtiness.

Mishnah Berurah (5): Women do fulfill and bless on Lulav. The Rema explains that Tzitzis is different, for it is not obligatory even on men.

Kaf ha'Chayim (5): The Levush says that it is also a problem of wearing a man's garment. The Ari Zal says that the Mitzvah does not apply to women at all.