A proverb meaning that even among close people one should keep manners and proper conduct (don't be overly familiar).
先輩に注意されたとき、彼は「近しき中に礼儀有り」と言われたのを思い出した。
When his senior scolded him, he remembered being told, 'Even among the close one must keep manners.'
夫婦でも、親しいからといって無礼になってはいけない。近しき中に礼儀有りだ。
Even between spouses you mustn't be rude just because you're close. 'Even among the close one must keep manners.'