Deuteronomy 10:17

כִּי ה’ אֱלֹקיכֶם הוּא אֱלֹקי הָאֱלֹהִים וַאֲדֹנֵי הָאֲדֹנִים הָקל הַגָּדֹל הַגִּבֹּר וְהַנּוֹרָא אֲשֶׁר לֹא יִשָּׂא פָנִים וְלֹא יִקַּח שֹׁחַד

Because Hashem your God, He is God of gods, and Lord of lords; God, great, mighty, and awe-inspiring, Who does not play favorites or take bribes.

The Talmud in tractate Brachos (33b) tells us of a person who ad-libbed in Shemoneh Esrei, calling G-d great, mighty, awe-inspiring, majestic, powerful, and a string of other praises. Rabbi Chaninah criticized him, saying that G-d’s praises are infinite; once one starts saying them, how can he ever stop? Rather, we just say that He is great, mighty and awe-inspiring, which is derived from Moshe’s use of those terms in this verse.