Baylonian Talmud, Berakhot, 33b

A particular individual descended before the ark as prayer leader in the presence of Rabbi Ḥanina. He extended his prayer and said: “God, the great, mighty, awesome, powerful, mighty, awe-inspiring, strong, fearless, steadfast and honored”. Rabbi Ḥanina waited for him until he completed his prayer. When he finished, Rabbi Ḥanina asked him: “Have you concluded all of the praises of your Master? Why do I need all of this superfluous praise? Even these three praises that we recite: The great, mighty and awesome, had Moses our teacher not said them in the Torah and had the members of the Great Assembly not come and incorporated them into the Amida prayer, we would not be permitted to recite them. And you went on and recited all of these. It is comparable to a king who possessed many thousands of golden dinars, yet they were praising him for silver ones. Isn’t that deprecatory?”

(Baylonian Talmud, Berakhot, 33b)