with one voice

English

(of vocalizing) In unison, together
- 1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], →OCLC, Acts 19:34:
  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.
- 1875, Louisa M[ay] Alcott, chapter 2, in Eight Cousins‎^[1]:
  Seven boys stood in a row all ages, all sizes, all yellow-haired and blue-eyed, all in full Scotch costume, and all smiling, nodding, and saying as with one voice, "How are you, cousin?"
(idiomatic, by extension, of expressing opinions by members of a group) In a mutually agreeing or like-minded manner; concordantly, unanimously.
- 1819, Sir Walter Scott, chapter 12, in Ivanhoe:
  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.
- 1916, Edith Wharton, Coming Home, section 3:
  Well—Jean went down and asked his father and his mother and his old grandmother if they would permit him to marry Mlle. Malo; and they all with one voice said they wouldn't.
- 2007 December 1, Bryan Walsh, “Can We Save the World by 2015?”, in TIme:
  Unfortunately, the global political community is a long way from speaking with one voice on anything, and climate change is no exception.

in unison