Every dog is valiant at his own door.
used to imply that people or animals tend to be more confident and assertive in their own familiar surroundings, and may show more courage when defending their own territory
People can be brave and confident when they feel secure in their own environment. This proverb suggests that people may be more willing to defend their own home or territory than they would be in unfamiliar surroundings. The proverb can also be used to describe people who are boastful or arrogant in familiar situations, but who become timid or unsure when taken out of their comfort zone.
People can act differently at home than they would in public. The proverb implies that people’s behavior at home may not be an accurate reflection of their true character, as they may be more comfortable expressing themselves in a familiar environment.