In the Eastern Han Dynasty , there was a man named Chen Shi .

　　在东汉初年，有个人叫陈寔。 　　One day, a thief slipped into his living-room. Hiding behind the beam, the thief waited for Chen Shi to fall asleep. 　　有一天，一个小贼溜进了他的房间，躲在房梁上等着陈寔去睡觉再下手。 　　Chen Shi, finding the thief, called his family together, saying, To be a upright man one must have aspirations. Men are not born evil. But if one gets used to doing evil things, it will be hard to reform. The gentleman above the beam is such a man. 　　陈寔发现了小偷，把他的家人都召集在一起，说：人不可以不自强。人不是天生就坏的，坏习惯往往是由不注意自身品性修养所致的。咱家房梁上这个人就是这样。 　　The thief, hearing this, hurriedly jumped down and knelt on the ground to beg forgiveness. 　　小偷听到这话，从房梁上跳到地上，跪在陈寔面前，请求原谅，决心做个有用的人。 　　This idiom is used to refer to a thief. 　　这个成语用来比喻小偷。