Sotah, Chapter Seven, Mishnah Four
This mishnah proves why the halitzah (release from Levirate marriage) must be recited in Hebrew.
How is it that the formula of halitzah [must be recited in Hebrew]?
[It is said] And she shall answer and say (Deuteronomy 25:9), and elsewhere it says, And the Levites shall answer and say (Deuteronomy 27:14); just as the answer made elsewhere must be in the holy tongue, so must the [declaration discussed here] be in the holy tongue.
Rabbi Judah says: And she shall answer and say thus, she must say it in this language.
The first opinion in the mishnah proves that the halitzah formula must be recited in Hebrew using the same midrash that yesterdays mishnah used to prove that the declaration made upon bringing the first fruits must be in Hebrew. Both mishnayoth connect the word say in this context to the say in the context of the Levitical curses and blessings.
Rabbi Judah derives this requirement without comparing the word say here with say elsewhere. Deut. 27:14 uses the word thus, a word which is somewhat superfluous. Rabbi Judah understands that word as teaching that the halitzah formula must be recited in Hebrew. Note that there is no halakhic debate between Rabbi Judah and the first opinion; there is only a debate on midrashic technique.