来而不往非礼也

1. • not to reciprocate is against etiquette (classical)
2. • to respond in kind

Character by character

• 来(lái)come
• 而(ér)and
• 不(bù)no
• 往(wǎng)go
• 非(fēi)not be
• 礼(lǐ)surname Li
• 也(yě)also