speak with one voice

to express the same opinion It is a very rare event when my family speaks with one voice about anything.

Usage notes: must refer to two or more people, as in the example

Name	Pronounced	Usage
Grga	-	Croatian
Gratian	GRAY-shən (English)	History
TunÇ	TOONCH	Turkish
Diarmuid	-	Irish, Irish Mythology
Finnr	-	Ancient Scandinavian
Gertrud	GER-troot (German)	German, Ancient Germanic