以直报怨，以德报德 以直報怨，以德報德 yǐ zhí bào yuàn , yǐ dé bào dé to repay kindness with kindness, and repay enmity with justice (idiom, from Analects)
以眼还眼，以牙还牙 以眼還眼，以牙還牙 yǐ yǎn huán yǎn , yǐ yá huán yá 1. an eye for an eye, a tooth for a tooth (idiom)2. fig. to use the enemy's methods against him3. to give sb a taste of his own medicine
以言代法，以权压法 以言代法，以權壓法 yǐ yán dài fǎ , yǐ quán yā fǎ 1. to substitute one's words for the law and abuse power to crush it (idiom); completely lawless behavior2. Might makes right.
可以意会，不可言传 可以意會，不可言傳 kě yǐ yì huì , bù kě yán chuán can be understood, but not described (idiom, from Zhuangzi 庄子[zhuāng zǐ]); mysterious and subtle
失之毫厘，谬以千里 失之毫厘，謬以千里 shī zhī háo lí , miù yǐ qiān lǐ a tiny lapse can lead to a huge mistake (idiom); a minor discrepancy leading to enormous losses
失之毫厘，差以千里 失之毫釐，差以千里 shī zhī háo lí , chà yǐ qiān lǐ a tiny lapse can lead to a huge mistake (idiom); a minor discrepancy leading to enormous losses
差之毫厘，谬以千里 差之毫釐，謬以千里 chā zhī háo lí , miù yǐ qiān lǐ 1. the slightest difference leads to a huge error (idiom)2. a miss is as good as a mile
幼吾幼，以及人之幼 yòu wú yòu , yǐ jí rén zhī yòu to care for other's children as one's own
星星之火，可以燎原 xīng xing zhī huǒ , kě yǐ liáo yuán a single spark can start a huge blaze (idiom); an insignificant cause can have a massive effect
物以类聚，人以群分 物以類聚，人以群分 wù yǐ lèi jù , rén yǐ qún fēn Similar things group together, similar people fit together (idiom); Birds of a feather flock together.
老吾老，以及人之老 lǎo wú lǎo , yǐ jí rén zhī lǎo to honor old people as we do our own aged parents
医之好治不病以为功 醫之好治不病以為功 yī zhī hào zhì bù bìng yǐ wéi gōng doctors like to treat those who are not sick so that they can get credit for the patient's "recovery" (idiom)
不以规矩，不能成方圆 不以規矩，不能成方圓 bù yǐ guī ju , bù néng chéng fāng yuán without rules, nothing can be done (idiom, from Mencius); one must follow some rules
授之以鱼不如授之以渔 授之以魚不如授之以漁 shòu zhī yǐ yú bù rú shòu zhī yǐ yú give a man a fish and you feed him for a day; teach a man to fish and you feed him for a lifetime (idiom)
授人以鱼不如授人以渔 授人以魚不如授人以漁 shòu rén yǐ yú bù rú shòu rén yǐ yú 1. give a man a fish and you feed him for a day; teach a man to fish and you feed him for a lifetime2. knowledge is the best charity
没有规矩，何以成方圆 沒有規矩，何以成方圓 méi yǒu guī ju , hé yǐ chéng fāng yuán without rules, how can anything be done (idiom); one must follow some rules
知其然而不知其所以然 zhī qí rán ér bù zhī qí suǒ yǐ rán (saying) to know that it is so but not why it is so
以小人之心，度君子之腹 yǐ xiǎo rén zhī xīn , duó jūn zǐ zhī fù to gauge the heart of a gentleman with one's own mean measure (idiom)
以其人之道，还治其人之身 以其人之道，還治其人之身 yǐ qí rén zhī dào , huán zhì qí rén zhī shēn 1. to use an opponent's own methods to obtain retribution (idiom, from Song dynasty neo-Confucianist Zhu Xi 朱熹[zhū xī])2. to get revenge by playing sb back at his own game; to give sb a taste of his own medicine
老吾老，以及人之老，幼吾幼，以及人之幼 lǎo wú lǎo , yǐ jí rén zhī lǎo , yòu wú yòu , yǐ jí rén zhī yòu to honor old people as we do our own aged parents, and care for other's children as one's own
(literary) to entrust with (a task); to appoint to (a role)
(literary) to entrust (sb) with an important task