Babylonian Talmud, Kiddushin 71a
1 א
תלמוד בבלי קידושין עא.
2 ב
א"ר יוחנן היכלא בידינו היא אבל מה אעשה שהרי גדולי הדור נטמעו בה סבר לה כר' יצחק דאמר ר' יצחק משפחה שנטמעה נטמעה
Rabbi Yohanan said: I [swear] by the Sanctuary that it is in our power [to reveal which families in the Land of Israel are genealogically tainted]! But what can I do? For behold, great people of the generation are mixed with them! Rabbi Yohanan agrees with Rabbi Yizchak, for Rabbi Yitzchak has said [once a genealogically tainted] family is mixed, it is mixed. [Translation by Rabbi Steve Greenberg]
3 ג
Time Period: Rabbinic (Maccabees through the Talmud)