Shabbat 138A

אלא אמר אביי: מדרבנן היא, שלא יעשה כדרך שהוא עושה בחול.

Rather, Abaye said: It is a rabbinic decree issued so that one will not conduct himself on Shabbat in the manner that he conducts himself during the week.

מנקיט אביי חומרי מתניתא ותני: הגוד והמשמרת, כילה וכסא גלין ⁠— לא יעשה, ואם עשה ⁠— פטור אבל אסור. אהלי קבע ⁠— לא יעשה, ואם עשה ⁠— חייב חטאת. אבל מטה וכסא טרסקל ואסלא ⁠— מותר לנטותן לכתחילה.

Abaye would consolidate the principles of the baraitot pertaining to the construction of a tent on Shabbat and teach: With regard to a large wineskin, a wine strainer, a canopy hung over a bed, and a folding chair whose cover is detached from its legs, one may not assemble them due to the prohibition against making a temporary tent. If one did so unwittingly, he is exempt by Torah law from bringing a sin-offering, but it is prohibited by rabbinic decree. With regard to permanent tents, one may not make them, and if he did so, he is liable to bring a sin-offering for performing the prohibited labor of building. However, with regard to a bed, and a folding chair [teraskal] whose cover is attached to its legs, and a collapsible toilet, it is permissible to open them ab initio, since they are prepared for use from before Shabbat.

ואין נותנין לתלויה בשבת. איבעיא להו: שימר מאי? אמר רב כהנא: שימר ⁠— חייב חטאת.

We also learned in the Mishnah: One may not place wine for filtering even into a suspended strainer on Shabbat. A dilemma was raised before the rabbis: If one strained wine, what is the halakha? Rav Kahana said: If one strained wine, he is liable to bring a sin-offering.

מתקיף לה רב ששת: מי איכא מידי דרבנן מחייבי חטאת, ורבי אליעזר שרי לכתחילה?!

Rav Sheshet strongly objects to this: Is there something for which the Rabbis render one liable to bring a sin-offering and R' Eliezer permits its performance ab initio? Extreme differences of opinion of that kind are rarely found in one Mishnah.