Русско-английский словарь пословиц и поговорок
В ЗАКРЫТЫЙ РОТ МУХА НЕ ЗАЛЕТИТ
There are times when it is better to keep silent not to get harmed or get into trouble
Cf:A closed mouth catches no flies (Am.). A close mouth catches no flies (Br.). A fish who keeps his mouth shut will never get caught (Am.). Into a mouth shut (a shut mouth) flies fly not (Br.)