小懲大誡

lit. to punish a little to prevent a lot (idiom); to criticize former mistakes firmly to prevent large scale repetition

small / tiny / few / young

to punish / to reprimand / to warn

see 大夫[dai4 fu5]

big; large; great / older (than another person) / eldest (as in 大姐[da4 jie3]) / greatly; freely; fully / (dialect) father / (dialect) uncle (father's brother)

commandment / to prohibit