Dictionary/来而不往非礼也

来而不往非礼也 來而不往非禮也

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ㄌㄞˊ ㄦˊ ㄅㄨˋ ㄨㄤˇ ㄈㄟ ㄌㄧˇ ㄧㄝˇ
Idiom
1not to reciprocate is against etiquette (classical)
2to respond in kind