This is the primary locus of the sugya: the Talmud records that Jeremiah and Daniel each omitted certain praises of God (fearsome and mighty) from their prayers because in their historical circumstances — the Temple destroyed, Israel enslaved — those attributes did not appear manifest. Rashi ad loc. explains ידעו את רבונם ששונא שקר, meaning 'they knew their Master that He hates falsehood,' and therefore removed praise they could not say with full truth.
וְהָא דְּרַב מַתְנָא מָטְיָיא לִדְרַבִּי יְהוֹשֻׁעַ בֶּן לֵוִי. דְּאָמַר רַבִּי יְהוֹשֻׁעַ בֶּן לֵוִי: לָמָּה נִקְרָא שְׁמָן אַנְשֵׁי כְּנֶסֶת הַגְּדוֹלָה — שֶׁהֶחְזִירוּ עֲטָרָה לְיוֹשְׁנָהּ. אֲתָא מֹשֶׁה, אָמַר: ״הָאֵל הַגָּדוֹל הַגִּבּוֹר וְהַנּוֹרָא״. אֲתָא יִרְמְיָה וַאֲמַר: גּוֹיִם מְקַרְקְרִין בְּהֵיכָלוֹ, אַיֵּה נוֹרְאוֹתָיו? לָא אֲמַר ״נוֹרָא״. אֲתָא דָּנִיאֵל אֲמַר: גּוֹיִם מִשְׁתַּעְבְּדִים בְּבָנָיו, אַיֵּה גְּבוּרוֹתָיו? לָא אֲמַר ״גִּבּוֹר״. אֲתוֹ אִינְהוּ וְאָמְרוּ: אַדְּרַבָּה, זוֹ הִיא (גְּבוּרַת) גְּבוּרָתוֹ: שֶׁכּוֹבֵשׁ אֶת יִצְרוֹ — שֶׁנּוֹתֵן אֶרֶךְ אַפַּיִם לָרְשָׁעִים. וְאֵלּוּ הֵן נוֹרְאוֹתָיו — שֶׁאִלְמָלֵא מוֹרָאוֹ שֶׁל הַקָּדוֹשׁ בָּרוּךְ הוּא הֵיאַךְ אוּמָּה אַחַת יְכוֹלָה לְהִתְקַיֵּים בֵּין הָאוּמּוֹת? וְרַבָּנַן: הֵיכִי עָבְדִי הָכִי וְעָקְרִי תַּקַּנְתָּא דְּתַקֵּין מֹשֶׁה? אָמַר רַבִּי אֶלְעָזָר: מִתּוֹךְ שֶׁיּוֹדְעִין בְּהַקָּדוֹשׁ בָּרוּךְ הוּא שֶׁאֲמִתִּי הוּא, לְפִיכָךְ לֹא כִּיזְּבוּ בּוֹ.
The Gemara comments: This interpretation that Rav Mattana said leans to, i.e., is consonant with, the exposition of Rabbi Yehoshua ben Levi. As Rabbi Yehoshua ben Levi said: Why are the Sages of those generations called the members of the Great Assembly? It is because they returned the crown of the Holy One, Blessed be He, to its former glory. How so? Moses came and said in his prayer: “The great, the mighty, and the awesomeGod” (Deuteronomy 10:17). Jeremiah the prophet came and said: Gentiles, i.e., the minions of Nebuchadnezzar, are carousing in His sanctuary; where is His awesomeness? Therefore, he did not say awesome in his prayer: “The great God, the mighty Lord of Hosts, is His name” (Jeremiah 32:18). Daniel came and said: Gentiles are enslaving His children; where is His might? Therefore he did not say mighty in his prayer: “The great and awesome God” (Daniel 9:4). The members of the Great Assembly came and said: On the contrary, this is the might of His might, i.e., this is the fullest expression of it, that He conquers His inclination in that He exercises patience toward the wicked. God’s anger is flared by the gentile nations’ enslavement of His people, yet He expresses tremendous might by suppressing His anger and holding back from punishing them immediately. Therefore, it is still appropriate to refer to God as mighty. And these acts also express His awesomeness: Were it not for the awesomeness of the Holy One, Blessed be He, how could one people, i.e., the Jewish people, who are alone and hated by the gentile nations, survive among the nations? The Gemara asks: And the Rabbis, i.e., Jeremiah and Daniel, how could they do this and uproot an ordinance instituted by Moses, the greatest teacher, who instituted the mention of these attributes in prayer? Rabbi Elazar said: They did so because they knew of the Holy One Blessed be He, that He is truthful and hates a lie. Consequently, they did not speak falsely about Him. Since they did not perceive His attributes of might and awesomeness, they did not refer to them; therefore, they cannot be criticized for doing so.