וַתֵּרָגְנ֤וּ בְאָהֳלֵיכֶם֙ וַתֹּ֣אמְר֔וּ בְּשִׂנְאַ֤ת יְהוָה֙ אֹתָ֔נוּ הוֹצִיאָ֖נוּ מֵאֶ֣רֶץ מִצְרָ֑יִם לָתֵ֥ת אֹתָ֛נוּ בְּיַ֥ד הָאֱמֹרִ֖י לְהַשְׁמִידֵֽנוּ׃
and ye murmured in your tents, and said: ‘Because the LORD hated us, He hath brought us forth out of the land of Egypt, to deliver us into the hand of the Amorites, to destroy us.
Rashi on Deuteronomy
ותרגנו — This is an expression denoting slander. Similar is, (Proverbs 18:8) “The words of a נרגן” i.e. of a man who brings a false report (Sifrei Devarim 24:1).
Sforno on Deuteronomy
בשנאת ה' אותנו, because we had worshipped idols while we were in Egypt.
Rashbam on Deuteronomy
ותרגנו, the word is derived from the same root as Proverbs 18,8 דברי נרגן כמתלהמים, “the words of a quarrelsome man are like afflictions.”