Shabbat 9A

דרך עליו, חייב! התם לא נח, הכא נח.

via the airspace above it, i.e., he raised the object more than 10 handbreadths above the ground of the public domain, which is an exempt domain, still he is liable for carrying in the public domain. On the other hand, in the Tosefta it says that if the object passed through an exempt domain, he is exempt by Torah law from punishment for passing it from domain to domain. The Talmud rejects that refutation as there is room to distinguish between the cases: There, in the halakha stated by Rava, the object did not come to rest in an exempt domain; it merely passed through its airspace. However, here, when transferred via the threshold, the object came to rest in an exempt domain, and as a result, the act of carrying out was divided into two separate actions, neither of which involves a Torah prohibition.

אחרים אומרים: אסקופה משמשת שתי רשויות: בזמן שהפתח פתוח ⁠— כלפנים. פתח נעול ⁠— כלחוץ.

Later in the Tosefta, Aḥerim say: Depending on the circumstances, a threshold serves two domains: When the entrance is open, the threshold is subsumed within the house and it is considered to be a private domain like the inside of the house. And when the entrance is locked, the threshold is not subsumed within the house, and it is considered to be a public domain like the outside.

ואף על גב דלית ליה לחי?! והאמר רב חמא בר גוריא אמר רב: תוך הפתח צריך לחי אחר להתירו!

The Talmud wonders: When the entrance is open the threshold is considered to be like a private domain, and is this so even though it does not have a post on its side? Didn’t Rav Ḥama bar Gurya say that Rav said: The opening in the wall, i.e., the doorway, requires another post in order to permit carrying there? A symbolic partition must be established at the side of the opening for that doorway to be considered closed and render carrying within it permissible like a full-fledged private domain. In the Tosefta, no mention was made of the need for a post of that kind.