גמרא יומא ע"א::ב'
ת"ר מעשה בכהן גדול אחד שיצא מבית המקדש והוו אזלי כולי עלמא בתריה כיון דחזיונהו לשמעיה ואבטליון שבקוהו לדידיה ואזלי בתר שמעיה ואבטליון.
The Sages taught in a braisa: There was an incident involving one High Priest who exited the Holy Temple and everyone followed him. When they saw Shemaya and Avtalyon, the heads of the Sanhedrin, walking along, in deference to them they left the High Priest by himself and walked after Shemaya and Avtalyon.
לסוף אתו שמעיה ואבטליון לאיפטורי מיניה דכהן גדול אמר להן ייתון בני עממין לשלם אמרו ליה ייתון בני עממין לשלם דעבדין עובדא דאהרן ולא ייתי בר אהרן לשלם דלא עביד עובדא דאהרן.
Eventually, Shemaya and Avtalyon came to take leave of the High Priest before returning to their homes. Envious of the attention they received, he angrily said to them: Let the descendants of the gentile nations come in peace. Shemaya and Avtalyon descended from converts, and he scornfully drew attention to that fact. They said to him: Let the descendants of the gentile nations come in peace, who perform the acts of Aaron, who loved and pursued peace; and let not a descendant of Aaron come in peace, who does not perform the acts of Aaron and who speaks condescendingly to descendants of converts.
An explanation of this puzzling exchange, Tal Oros Page 55 and on.
