身(み)の程(ほど)one's social position, one's place, one's standing

上司(じょうし)：「君(きみ)は身(み)の程(ほど)を弁(わきま)えるべきだよ。」

Boss: "You should know your place."

主人(しゅじん)：「お前(まえ)は奴隷(どれい)なんだ！この身(み)の程(ほど)知(し)らずが！」

Master: "You're a slave! Know your place, you insolent fool!"

さっきは身(み)の程(ほど)を弁(わきま)えずに偉(えら)そうな事(こと)を言(い)ってしまいました。

Earlier, I spoke arrogantly without understanding one's social position.

まだ議員(ぎいん)３(さん)年(ねん)目(め)の新人(しんじん)なのに会長(かいちょう)選(せん)に立候補(りっこうほ)するとは身(み)の程(ほど)知(し)らずだ。

Even though he is still a rookie in his third year as a member of the assembly, it is reckless of him to run for chairman, not knowing one's place.

彼女(かのじょ)は上司(じょうし)に「身(み)の程(ほど)を知(し)れ！」と言(い)われた事(こと)に傷(きず)ついて辞職(じしょく)したのだとか。

She was hurt when her boss told her to "know one's place!" and ended up resigning.