Megillah 10A

יש אחריה היתר, וקדושת ירושלים ⁠— אין אחריה היתר.

after the Tabernacle was destroyed, there is permission to sacrifice offerings on improvised altars. But with regard to the sanctity of Jerusalem, after the Temple was destroyed, there is no permission to sacrifice offerings on improvised altars, as the prohibition remains intact.

גמ׳ אמר רבי יצחק: שמעתי שמקריבין בבית חוניו בזמן הזה. קסבר: בית חוניו לאו בית עבודה זרה היא, וקא סבר: קדושה ראשונה ⁠— קידשה לשעתה ולא קידשה לעתיד לבוא.

Talmud: R' Yitzḥak said: I heard that one sacrifices offerings in the temple of Onias in Egypt at the present time. The Talmud cites the basis for the statement of R' Yitzḥak. He maintains that the temple of Onias is not a house of idol worship but rather a temple devoted to the service of God, and he maintains that the initial consecration sanctified Jerusalem for its time and did not sanctify Jerusalem forever. Therefore, after the destruction of the Temple, the sanctity of Jerusalem lapsed and the sacrifice of offerings elsewhere was no longer prohibited. For these reasons it was permitted to sacrifice offerings in the temple of Onias after the Temple was destroyed.

דכתיב: ״כי לא באתם עד עתה אל המנוחה ואל הנחלה״. ״מנוחה״⁠ — זו שילה, ״נחלה״⁠ — זו ירושלים, מקיש נחלה למנוחה: מה ״מנוחה״ יש אחריה היתר, אף ״נחלה״ יש אחריה היתר.

The Talmud cites the source of this halakha. It is as it is written: “For you are not as yet come to the rest and to the inheritance” (Deuteronomy 12:9), which is interpreted: “Rest,” this is Shiloh; “inheritance,” this is Jerusalem. The verse juxtaposes and likens inheritance to rest: Just as in the place of rest, Shiloh, after its destruction there is permission to sacrifice offerings on improvised altars, so too in the place of inheritance, Jerusalem, after its destruction there is permission to sacrifice offerings on improvised altars.

אמרו ליה: אמרת? אמר להו: לא. אמר רבא: האלהים! אמרה, וגמירנא לה מיניה.

The Talmud reports that the other rabbis said to R' Yitzḥak: Did you say this halakha with regard to the temple of Onias? He said to them: No, I did not say that. Rava said, reinforcing his assertion with an oath: By God! R' Yitzḥak did in fact say this, and I myself learned it from him, but he later retracted this ruling.