discretion is the better part of valour
It is often wise to refrain from seemingly brave, but dangerous, speech or action.
The better part of valour is discretion; in the which better part, I have saved my life.
ADJ
great
The firefighters displayed great valour when they rushed into the burning building to rescue the family.
VERB + VALOUR
demonstrate, display, show
The firefighters displayed remarkable valour while rescuing people from the burning building.
PREP
an act/a deed of valour