Gemara

Question: May one go out on Yom Kipur wearing sandals made of rush (a kind of reed or bark)?

Answer: R. Yehoshua ben Levi did so;

Rav Yehudah, Abaye and Rava went out on Yom Kipur wearing sandals made of Hitni (a kind of rush), Lulavim, and grass, respectively. Rabah bar Rav Huna went out with a cloth wrapped on his foot.

Question (Rami bar Chama): R. Meir and R. Yosi argue about whether or not one who is missing a foot may go out in Reshus ha'Rabim on Shabbos with a Kav (false foot. It houses what remains of his leg; it is a shoe for him). All forbid wearing it on Yom Kipur (even though R. Yosi does not consider it to be a shoe)!

Answer #1 (Abaye): There it is forbidden because it has tufts inside for comfort.

Objection #1 (Rava): If without tufts it is not a shoe, tufts do not make it a shoe! The only comfort forbidden on Yom Kipur is wearing shoes;

Rabah bar Rav Huna went out with a cloth wrapped on his foot!

Objection #2 (Rava): Also, the Seifa says that if it has a receptacle for tufts, it is Mekabel Tum'ah. This shows that in the Reisha it does not have tufts!

Answer #2 (Rava): All agree that it is a shoe. Regarding Shabbos, R. Yosi decrees not to wear it lest it fall off and he will carry it four Amos (in Reshus ha'Rabim). R. Meir does not decree.

Beraisa: A Yoledes may wear sandals to protect from the cold.

Shmuel: It is permitted (to anyone) on account of scorpions.

Rishonim

Rif: Question: May one go out on with sandals of rush?

Answer: R. Yehoshua ben Levi did so. Rav Yehudah, Abaye, Rava and Rabah bar Rav Huna went out with sandals made of Hitni, Lulavim, grass, and a cloth wrapped on his foot, respectively. (The Rif does not bring Rami bar Chama's question or the answers to it.)

Ran: The question was whether or not a rush sandal is considered a shoe. Also, even if it is not, perhaps it is forbidden because it protects. The Rif concludes that only leather shoes are forbidden. Ba'al ha'Ma'or argues, for Rava concludes that anything that protects is considered a shoe. Rashi holds that only what is made of wood (or leather) is considered a shoe.

Lechem Mishneh (Hilchos Shevisas Asor 3:7): The Rif did not say that wooden shoes are permitted! The Rif (and similarly, the Rambam) holds that the Amora'im who went out with the various sandals hold like R. Yochanan ben Nuri (Shabbos 66a) who does not consider a plasterer's shoe to be a shoe.

Rif: Anything to protect from scorpions is permitted.

Rambam (Hilchos Shevisas Asor 3:7): One may go out with sandals made of rush, reeds or similar things (other than leather). One may wrap a cloth on his foot and go out, for he will still feel the hard ground, so it is as if he is barefoot.

Source (R. Mano'ach): Socks are also permitted, for this is comfort without a shoe. The Yerushalmi permits Anpilyos (soft shoes) of cloth, but forbids Anpilyos of leather and sandals. Some say that only leather is forbidden. This is wrong, for Rava forbids a Kav!

Rambam (ibid. 8): Anyone may wear a sandal in a place of scorpions or other creatures that bite.

Rosh (8:7): We learn from R. Yehoshua ben Levi that one may go out with sandals of rush. Rav Yehudah, Abaye, Rava and Rabah bar Rav Huna went out with sandals of Hitni, Lulavim, grass, and a cloth. The Gemara in Yevamos (102b) permits cloth socks in the house and forbids leather socks. Some infer that cloth socks are permitted only in the house. This is wrong. Rather, the Gemara discussed in the house to teach that even this is forbidden regarding leather socks. Surely cloth socks are permitted outside, for they protect less than sandals of rush and Hitni.

Rosh (8:9): Anyone may wear a sandal or shoe where it is dangerous to go barefoot due to scorpions.

Poskim

Shulchan Aruch (OC 614:2): One may not wear a leather sandal or shoe, even a Kav. Even if it is wooden and covered with leather it is forbidden. Shoes of reeds, straw, cloth or other materials are permitted even in Reshus ha'Rabim. (This is Malbush (wearing), not carrying.)

Beis Yosef (DH veha'Rambam, DH v'Chosav ha'Ran): It is not clear how the Rambam holds. We follow the Rif and Rosh, who permit everything except for leather. R. Yerucham forbids a wooden shoe to a mourner. He would similarly forbid on Yom Kipur.

Magen Avraham (2): The Bach says that it is proper to walk totally barefoot. Also, even an Istnis should not wear socks where it is forbidden to carry, for it is carrying. The Ran is lenient, and this is our custom.

Taz (1): One should not consider himself more righteous than the Amora'im, who wore sandals of other materials l'Chatchilah.

Rema: One may stand on top of leather pillows and blankets. However, one who is stringent will be blessed.

Beis Yosef (DH u'Mah she'Chosav v'Chen): The Or Zaru'a permits torn leather shoes. Presumably, this is even if the bottom is intact. All the more so, one may stand on top of leather pillows and blankets!

Magen Avraham (4): The Radvaz holds that there is no reason to be stringent about this.

Shulchan Aruch (ibid. 4): Anyone may wear a sandal in a place of scorpions or other creatures that bite.

Rema: If it rained and one wants to go to or from the Beis ha'Keneses and he is an Istnis, he may wear shoes until reaching his destination.

BaHaG (brought in Taz 2): If one is delicate, or if for the needs of the day or a Mitzvah he must go where scorpions are found, he may wrap something around his foot.

Question (Tur): It is permitted to protect from scorpions or to go to do a Mitzvah, and in either case one may wear even shoes!

Answer #1 (Beis Yosef DH Kosav): BaHaG explains that Shmuel permits the minimum necessary to protect from scorpions. BaHaG teaches that the same is permitted whether or not it is for a Mitzvah.

Answer #2 Taz (2): Shmuel did not say 'and similarly...' Rather, he said 'it is permitted'. BaHaG derives from this that Shmuel teaches an additional Chidush. Where there is danger from scorpions, shoes are permitted, and one may even wrap something around his foot and go in Reshus ha'Rabim. It is not considered carrying, rather, Malbush. This is like the Ran, who says that since one may not wear leather shoes on Yom Kipur, it is normal to wear shoes of other materials, so this is Malbush.

Mishnah Berurah (12): Istnis refers to one whose health will be harmed if he goes without shoes. It is forbidden for others, unless the ground is muddy, for then everyone is like an Istnis. Magen Avraham (5) says that someone wearing socks is not pained, so he should not wear shoes.

Mishnah Berurah (13): One must remove the shoes the moment he reaches a place where he will not be harmed without them. When one must wear shoes, it is better to wear them on the wrong feet. It is better to wear sandals without a heel (Sha'ar ha'Tziyon 18).

Mishnah Berurah (14): One should try to touch the shoes only through a cloth; if his hand touched them, he must wash the part that touched.

Kaf ha'Chayim (28): If one must walk in a dirty place, it is better to walk barefoot and wash his feet than to walk through with shoes, even though both of these are mid'Rabanan (Nimukei Yosef Yevamos 33a DH Garsinan). He should try to avoid stepping in water, for one may not wash even his pinky for pleasure.

Kaf ha'Chayim (34): Even if one must walk among Nochrim who will mock him, he may not wear shoes to avoid ridicule because some say that the Isur is mid'Oraisa. However, it is permitted on Tish'ah b'Av.