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To stop a bad idea or action at its inception so that it does not become worse
Positive
坏习惯往往都是在不经意中养成的，为了防微杜渐，千万得事事小心 | Huài xíguàn wǎngwǎng dōu shì zài bùjīngyì zhōng yǎngchéng de, wèile fángwēidùjiàn, qiān wàn děi shìshìxiǎoxīn
Bad habits are often formed due to lack of attention. In order to nip them in the bud, you must be very careful
[Source]
今天我们所以要注意这些小地方，目的在防微杜渐，免得日后酿成大问题 | Jīntiān wǒmen suǒyǐ yào zhùyì zhè xiē xiǎo dìfāng, mùdì zài fángwēidùjiàn, miǎndé rìhòu niàngchéng dà wèntí
The reason we're focusing on these small things today is so that they don't stew into larger issues in the future
[Source]
Nip it in the bud
杜渐防微 (dù jiàn fáng wēi)
None
《启谏冉闵》 (Qǐ Jiàn Rǎn Mǐn), a work by 韦謏 (Wéi Xiǎo) of the Jìn Dynasty (晋, 265 - 420)
During the Eastern Hàn Dynasty (东汉, 25 - 220), there lived a man named 丁鸿 (Dīng Hóng). His parents passed away of an illness while they were out at war, and as was the law at the time, he inherited his father's position in the government.
Later, the emperor 和帝 (Hé Dì) ascended to the throne, but the 窦太后 (the empress dowager Dòu) amassed a substantial amount of power. On top of that, her elder brother was an important figure in the military, and between the two of them, they effectively controlled the entire political and military power of the country. Members of the court knew this, but they were too afraid to say anything or do anything.
丁鸿 was amongst those who knew of power of the 窦s, but he needed to wait for the right opportunity to act. A few years later, a solar eclipse occurred. At the time, this was considered a bad omen, so 丁鸿 quickly found the emperor.
"Your Majesty," he told his ruler. "In the 37 recorded eclipses that have occurred throughout history, 32 of them have ended with ministers killing the emperor. It is all because the ministers became too powerful!" He then added, "The water that carves through cliffs one day began as a mere trickle; and the trees scraping the heavens one day were once mere branches who had just had seen their first sprouts of green. Small things often grow into big things unseen, and then those big things become calamities. Sire, don't you think that the power of the 窦 family is just like this?"
His words relieved the emperor greatly, as he had harbored such fears himself. He stripped the empress dowager of her rank, leading both the empress dowager and her brother to commit suicide.