with one voice

prepositional phrase2

1. •
   In unison, together

   • But when they knew that he was a Jew, all with one voice about the space of two hours cried out, Great is Diana of the Ephesians. — 1611
2. •
   In a mutually agreeing or like-minded manner; concordantly, unanimously.

   • The nobles around Prince John implored him with one voice to throw down his warder, and to save so brave a knight from the disgrace of being overcome by odds. — 1819