wú shì bù dēng sān bǎo diàn

ㄨˊ ㄕˋ ㄅㄨˋ ㄉㄥㄙㄢㄅㄠˇ ㄉㄧㄢˋ

Idiom

1lit. one doesn't visit a temple without a cause (idiom)

2fig. to visit sb with an ulterior motive (esp. to ask for sth)