Kiddushin 21A

הא רבנן, הא רבי שמעון.

This second baraita is in accordance with the opinion of the Rabbis, and that baraita, which teaches that one can borrow money and redeem the house and partially redeem it, is in accordance with the opinion of R' Shimon.

תני חדא: לוה וגואל וגואל לחצאין, ותניא אידך: אין לוה וגואל וגואל לחצאין. לא קשיא, הא רבנן, הא רבי שמעון.

The Talmud states: It is taught in one baraita with regard to the houses of walled cities: One can borrow money and redeem it, and one can partially redeem it, and it is taught in another baraita: One cannot borrow money and redeem it, nor can one partially redeem. Apparently, there is a contradiction between these two baraitot. The Talmud answers as above: This is not difficult. This baraita is in accordance with the opinion of the Rabbis, and that baraita is in accordance with the opinion of R' Shimon.

(סימן: חרש חבש זמן)

The Talmud provides a mnemonic device for the names of the rabbis who raise the dilemmas cited below and those to whom the questions are addressed: Ḥeresh, ḥavash, zeman. They allude to the following interlocutors: Ḥeresh alludes to Rav Aḥa, son of Rava, and Rav Ashi; ḥavash alludes to Rav Aḥa Sava and Rav Ashi; and zeman alludes to Mar Zutra, son of Rav Mari, and Ravina.

אמר ליה רב אחא בריה דרבא לרב אשי: איכא למיפרך: מה למוכר בית בבתי ערי חומה ⁠– שכן הורע כחו ליגאל לעולם, תאמר במקדיש ⁠– שיפה כחו ליגאל לעולם!

Rav Aḥa, son of Rava, said to Rav Ashi: The comparison detailed earlier (20b) between one who sells a house and one who consecrates a field, can be refuted as follows: What is unique about one who sells a house among the houses of walled cities is that his power is diminished, in that he is not able to redeem it forever, since he cannot redeem it after a year has passed (see Leviticus 25:30). should you say the same with regard to one who consecrates his field, as his power is enhanced in that he is able to redeem forever?