Dripping water penetrates stone
Indicates that small efforts can achieve great results if expended continuously over a long period of time
Positive
他每天坚持学习汉语，水滴石穿最后终于取得成功，汉语达到了很高的水平 | Tā měitiān jiānchí xuéxí hànyǔ, shuǐdīshíchuān zuìhòu zhōngyú qǔdé chénggōng, hànyǔ dádào le hěn gāo de shuǐpíng
He persevered in studying Chinese every day and finally has achieved success: his Chinese has reached a very advanced level
[Source]
没有水滴石穿的功夫，也是不可能写完这本书的 | Méiyǒu shuǐdīshíchuān de gōngfū, yěshì bù kěnéng xiě wán zhè běn shū de
Without persistent hard work, I would never have been able to finish writing this book
[Source]
Slow and steady wins the race
Persistence pays off
滴水穿石 (dī shuǐ chuān shí)
Though the《汉书》(Hàn Shū) is the original source of this chengyu, the story below comes from the work that popularized the chengyu, 《鹤林玉露》(Hè Lín Yù Lù) by Sòng Dynasty (宋, 960 - 1279) author 罗大经 (Luó Dà Jīng)
《汉书》(Hàn Shū), a work documenting the history of the Western Han dynasty (西汉, Xī Hàn, 206 BC - 8 AD). It was written by 班固 (Bān Gù), and is generally known in English as the "Book of Han" or the "History of the Former Han."
During the Sòng Dynasty (宋, 960 - 1279) there lived a county magistrate named 张乖崖 (Zhāng Guāi Yá). One day, he ran into a low-ranking court official who was coming out of the treasury, and he spotted a coin beneath his turban. Immediately, he started questioning the man, and after ascertaining his guilt, he ordered him beaten with clubs.
The official resisted the punishment furiously, claiming, "It was a tiny amount of money! Besides, you can only beat me over this, not kill me!"
张乖崖 asserted, "A single coin stolen once a day over a thousand days becomes a thousand stolen coins; a tree will eventually be cut after repeatedly sawing at it with a rope; and water, dripping continuously, will eventually pierce through even stone."
And with this judgement made, he then personally executed the thief.