Carrying Four Amos in a Public Domain
Hotza'ah has another basic form that does not require crossing from one domain into another. Carrying an object four amos within reshus harabim is itself a Torah prohibition.
The Alter Rebbe states: “הֲלָכָה לְמֹשֶׁה מִסִּינַי שֶׁהַמַּעֲבִיר חֵפֶץ ד' אַמּוֹת בִּרְשׁוּת הָרַבִּים חַיָּב” (Shulchan Aruch Harav, Orach Chaim 346:5). He then devotes siman 349 to the measurement and mechanics of those four amos.
Four amos within the same reshus harabim
The prohibition applies even when the object never leaves reshus harabim. A person can begin and end in the same halachic domain and still perform the Torah melacha by carrying the object the required distance.
The Alter Rebbe explains that a person is given four amos in which he can move an object in reshus harabim. The measure is related to the person's own body measure, with further rules for unusual body size and for the exact geometric calculation (Shulchan Aruch Harav 349:1-2; Shulchan Aruch, Orach Chaim 349:1-2).
For understanding the melacha, the main point is that “less than four amos” and “four amos” are halachically different distances. It is not enough to say that someone stayed in one street or never crossed a property line.
A complete carrying act
The Alter Rebbe explains that the Torah-level act of carrying four amos is completed when the object is carried through the required distance as one continuous act. If the person stops within the four amos for a genuine rest and then continues, the movement is no longer the same uninterrupted Torah act (Shulchan Aruch Harav 349:3).
But this distinction cannot be turned into an ordinary method of carrying. Chazal prohibited deliberately carrying in repeated segments of less than four amos, even if the person pauses or puts the object down between segments, because that can easily lead to carrying the full distance in one continuous movement.
The nature of a stop also matters. A pause to rest is not the same as a pause made only to adjust or settle the load. The Alter Rebbe treats a stop made merely to correct the load as part of the ongoing walk rather than as a true interruption.
These rules illustrate a recurring feature of hotza'ah. Halacha considers where the person is standing, the state of the object, the distance moved, and whether there has been a halachically significant akirah or hanachah.
Four amos in a karmelis
A karmelis is not a complete reshus harabim min haTorah, so carrying four amos there is not the same Torah-level case. Chazal nevertheless prohibited carrying four amos in a karmelis (Shulchan Aruch Harav 346:5).
The Alter Rebbe also applies the rabbinic safeguard against carrying by repeated short segments in a karmelis during Shabbos itself (Shulchan Aruch Harav 349:3). The practical result is that calling a street or open area a karmelis does not create general permission to carry there.
The classification of a street as a complete reshus harabim or a karmelis affects the level and structure of the prohibition and the enclosure required to permit carrying. The definition of a modern reshus harabim is treated separately in Reshus Harabim in a Modern City.
What changes inside a valid reshus hayachid
The four-amos prohibition described here is the rule of carrying in reshus harabim, with a rabbinic parallel in karmelis. Once an area is validly enclosed and has the status required for permitted carrying, the reshus harabim rule of four amos is no longer the governing prohibition within that area.
That statement has limits. Some enclosures that are reshus hayachid min haTorah can still carry separate rabbinic restrictions, and an enclosed area shared by different residents can require an eruv chatzeiros or related communal arrangement. A physical perimeter and a communal eruv therefore do different work.
Those two layers are explained in How a Valid Eruv Changes the Practical Status of Carrying. The practical halachos of ordinary items, strollers, keys, food, and similar cases belong to the separate Practical Halachos of Carrying in Crown Heights section.