a thief in the family is difficult to detect

a thief in the family is difficult to detect

It's hard to guard against domestic thieves. Chinese idiom, Pinyin is Ji ā Z é in á NF á ng, which means that it's hard to guard against domestic thieves. It means that it's not easy to guard against bad people hidden inside. It comes from five Lantern Festival, Yuan Dynasty, Tongan Zhixiang shifasi.

The origin of Idioms

Shi Puji of the Song Dynasty wrote "five Lantern Festival yuan: Tongan Zhixiang shifasi": "how about when it's hard to guard against thieves?" The teacher said, "it's not wrong to know."

Idiom usage

It is the most difficult to guard against the bad people inside.