Arakhin 14A

מלתא אגב אורחיה קמשמע לן, כדרב יהודה אמר רב, דאמר רב יהודה אמר רב: אסור לאדם שיאמר ״כמה נאה גוי זה״.

by not mentioning non-Jews, the Mishnah teaches us another matter in passing, in accordance with the statement that Rav Yehuda says that Rav says. As Rav Yehuda says that Rav says: It is prohibited for a person to say: How beautiful is this non-Jew.

וליתני ״את הנאה שבישראל ואת הכעור שבגוים״! בחד אומה קמיירי, בתרי אומי לא מיירי.

The Talmud asks: But if this is the only reason that a non-Jew is not mentioned, let the Mishnah teach: In the case of one who took a vow of valuation to donate the fixed value of the most attractive among the Jewish people and the most unsightly among the non-Jews, he gives the fixed payment of 50 sela to the Temple treasury. The Talmud answers: The tanna prefers to deal with one nation, i.e., Jews, and does not wish to deal with two nations, Jews and non-Jews.

ולא? והא קתני: הגדולה שבכהונה ואת הקטנה שבישראל! התם חד אומה הוא, אלא מקדיש הוא דקדישי כהנים טפי.

The Talmud challenges this answer: And does the Mishnah not deal with two nations? But isn’t it taught in a Mishnah (14b): One who raped or seduced a young woman, whether she is the most prominent in the priesthood or the lowliest among the Israelites, gives the payment of 50 sela, the fine stated in the Torah. Priests and Israelites are two distinct groups of people, analogous to Jews and non-Jews. The Talmud answers: In that Mishnah there it is one nation, as although there are two groups they are both part of the Jewish people. It is only that the priests have greater sanctity than Israelites.

ואיבעית אימא, איידי דקא בעי למתני סיפא ״שדה אחוזה״, דבישראל הוא דמשכחת לה, בגוי לא משכחת לה, דלאו בני אחוזה נינהו, משום הכי קתני לה בישראל.

And if you wish, say instead that since the Mishnah wants to teach the case of an ancestral field in the latter clause, which you find in the case of Jews, but you do not find with regard to non-Jews, as they are unfit to have ancestral land in Eretz Yisrael, it is due to this reason that the Mishnah teaches only cases that involve the Jewish people.