WHEN IS IT FORBIDDEN TO PASS OVER MITZVOS? [Mitzvos:Ma'avirin]
(Mishnah): The Shirayim (are poured on the Yesod on the western side of the outer Mizbe'ach.)
We learn from "El Yesod Mizbach ha'Olah Asher Pesach Ohel Mo'ed", which refers to the Yesod closest to the opening of Ohel Mo'ed (or Heichal, in the Mikdash), the first side the Kohen encounters (after leaving the Heichal).
53a (Beraisa): (Shirayim of outer Chata'os are poured) "El Yesod ha'Mizbe'ach" - the southern Yesod;
Question: Perhaps it refers to the western Yesod! We learn what is unspecified (outer Chata'os) from what is explicit (inner Chata'os).
Answer: (Indeed, we learn from inner Chata'os, but differently.) Just like Shirayim of inner Chata'os are poured on the first Yesod encountered (after leaving the Heichal), Shirayim of outer Chata'os are poured on the first Yesod encountered (after descending from the ramp).
58b (Beraisa - R. Yosi): Whatever is taken from inside to be put outside is put in the closest possible place.
Suggestion: This refers to Shirayim (of inner Chata'os).
Rejection: A verse explicitly teaches this - "El Yesod Mizbach ha'Olah Asher Pesach Ohel Mo'ed"!
Yoma 33a (Reish Lakish): We do not pass over Mitzvos.
Menachos 64b (Mishnah): L'Chatchilah, the Omer must be brought from a place close (to Yerushalayim).
This is because the Omer must be Karmel (soft). Alternatively, we do not pass over Mitzvos.
Megilah 6b: R. Eliezer holds that even in a leap year, we celebrate Purim in the month next to Shevat. This is because we do not pass over Mitzvos.
Tosfos (51a DH Asher): The text should not say 'the first side the Kohen encounters.' This would imply that we learn from reasoning, and not from the verse. On 53a, we suggested learning outer Chata'os, for which the Torah did not specify where to put the Shirayim, from inner Chata'os, which are explicit. This shows that the verse explicitly teaches it; it is not from reasoning. Also, some learn that they are on the south from inner Chata'os, in which the Shirayim are poured on the first Yesod encountered. Why was the law of inner Chata'os clearer than that of outer Chata'os? The same reasoning applies to both! Also, on 58b we say that the verse explicitly teaches about Shirayim, so surely the rule 'whatever is taken... is put in the closest possible place' was not needed to teach about Shirayim. Why is the verse needed? We should know without it, due to Ein Ma'avirin Al Mitzvos! This principle taught on which corner we begin to put Dam Chatas and whether we first remove ashes from the inner Mizbe'ach or the Menorah (Yoma 15b)! We must say that Ein Ma'avirin applies only when both are in front of us and we do not know which to do first, e.g. Dishun of the inner Mizbe'ach or the Menorah. It would not determine the place to put Shirayim.
Note - also Tosfos (Menachos 64b DH Iba'is) and Piskei Tosfos (Yoma 58b 36) say that Ein Ma'avirin teaches only about which Mitzvah to do first.
Rebuttal #1 (Shitah Mekubetzes Menachos 64b:11): The Gemara says that Ein Ma'avirin applies to the Omer, even though there is only one Mitzvah to do.
Rebuttal #2 (Tosfos Megilah 6b DH Mistaber): R. Eliezer b'Rebbi Yosi says that we read the Megilah in Adar Rishon because Ein Ma'avirin Al Mitzvos, even though there is only one Mitzvah to do.
Defense (Yad Binyamin Menachos 64b DH v'Lashon and DH v'Achen): Tosfos teaches that if the Torah fixed a place for a Mitzvah, e.g. on which side of the Mizbe'ach blood must be put, Ein Ma'avirin cannot determine the place. Tosfos agrees that Ein Ma'avirin applies to one Mitzvah when the Torah did not fix a place. The Malbim explains that Tosfos says that Ein Ma'avirin overrides Tadir (the more frequent Mitzvah) only when there are two Mitzvos to do. When there is only one Mitzvah, we pass over a Mitzvah to do what is more Tadir.
Shulchan Aruch (OC 25:1): After putting on a Talis he puts on Tefilin, for we ascend in Kedushah. If one puts his Talis and Tefilin in the same bag, he should not put the Tefilin on top, lest (next time) he encounters the Tefilin first and he will have to put them on first, to avoid passing over the Mitzvah.
Beis Yosef (DH v'Acher): If one took out his Tefilin Shel Rosh before Shel Yad, he must put it aside and put the Shel Yad on first. The order specified by the Torah overrides passing over Mitzvos. The Nimukei Yosef disagrees, but his is the minority opinion. However, if one took out Tefilin before his Talis, he must put Tefilin on first. Not passing over Mitzvos overrides an Asmachta that Talis should be first.
Question (Magen Avraham 1): If the Tefilin are in a bag, passing over Mitzvos should not apply! The Shulchan Aruch itself says not to take the Tefilin Shel Rosh out of the bag until the Shel Yad is properly placed!
Mishnah Berurah (1): He should put on the Talis first even if it is obligated only mid'Rabanan, e.g. it is borrowed.
Mishnah Berurah (3): Even if he did not touch the Tefilin, if they are closer when he sticks out his hand he must put them on first. This is only if he wants to put them on now. If he does not intend to put them on until later, passing over Mitzvos does not apply.
Mishnah Berurah (28:8): One should not remove the Shel Yad until he puts away the Shel Rosh, lest he put the Shel Yad in the bag first.
Rema: If Tefilin are available but not Tzitzis, he need not wait for Tzitzis. He puts on the Tefilin, and when the Talis comes he puts it on.
Mishnah Berurah (Sof Siman 34): If one removed the bag with R. Tam Tefilin first, he puts them aside because we hold that Rashi Tefilin are primary. L'Chatchilah, one should ensure that this does not happen.
Beis Yosef (36, letter Tes): We must say that the right 'head' of the letter 'Tes' is not flat. If it was, we would put the crowns on it. (We would not wait to put them on the left head, due to Ein Ma'avirin.)
Rema (473:4): One should arrange the Seder plate so he will not need to pass over Mitzvos. The Karpas should be closest to him, then the vinegar, Matzah, Maror and Charoses, and the meat and egg should be furthest.
Source (Gra DH v'Yesader): We learn from Yoma 33b.
Chak Yakov (16): The Maharil says that the Karpas should be closer than the Matzah, for if the Matzah was closer he would need to cut the Afikoman first. He did not mention the Charoses, meat and egg. Since we do not bless on them, they are mere commemorations and Ein Ma'avirin Al Mitzvos does not apply to them. Some say that Charoses is not a Mitzvah. He mentioned Matzah because we bless 'v'Tzivanu' on it and its Berachah should be before Borei Peri ha'Adamah. He did not mention Maror, even though we bless 'v'Tzivanu' on it. Perhaps this is because people do not enjoy it, and its Berachah does not have priority.
Mishnah Berurah (26): See the Acharonim who bring the Seder of the Ari Zal.
Shulchan Aruch ha'Rav (26): Some (are not concerned for Ein Ma'avirin) and have a different Seder (according to the Ari Zal).
Kaf ha'Chayim (58): The Ari Zal says that the 10 Sefiros correspond to what is on the Seder plate, and they should be in the proper places. The three Matzos (from top to bottom) correspond to Chachmah, BInah and Da'as. Next to them (further away - PF) are the Zero'a on the right, the Beitzah on the left, and Maror in the middle, corresponding to Chesed, Gevurah and Tiferes, respectively. Charoses is in back of the Zero'a, on the right. Karpas is in back of the Beitzah on the left. Chazeres (Romaine lettuce) is in back of the Maror in the middle. These correspond to Netzach, Hod and Yesod. The plate itself corresponds to Malchus. Salt water or anything else should not be on the plate until after eating Matzah and Maror.
Rema (669:1): If a Tzibur has only two Sifrei Torah, on Simchas Torah they read v'Zos ha'Berachah in the first, from Bereishis in the second, and the Maftir in the first. The same applies whenever there is a Mitzvah to read from three Sifrei Torah and there are only two Sifrei Torah.
Bi'ur Halachah (DH v'Chozrin): This is only if the first was already rolled to the place for Maftir, so the Tzibur will not need to wait. If not, we read in the second to avoid passing over Mitzvos (even though we must roll the second about four times as much as we would have to roll the first - PF).