"A promise of a thousand dollars, a promise of a thousand dollars" comes from The Analects of Confucius Yan Yuan.

"The Analects of Confucius Yan Yuan": "The words of the master are also gentlemen." "Deng Xi's Biography": "A word is inconsistent, and the horse cannot be chased; In a hurry, the horse can't reach. " I mean, in a word, even four horse-drawn cars are hard to catch up with. When you say something, you can't take it back. You must keep your promise.

"Once a word is spoken, it is difficult to recall it." Y and y á n j ū ch ū s m n Zhu has. Xu: Four horses rode together in ancient times; Or a chariot with four horses: ~ Jie (a chariot driven by four armored horses). In a word, even four good horse-drawn cars are hard to catch up with. When you say something, you can't take it back. You must keep your promise.

Extended data allusions:

During the Spring and Autumn Period, there was a doctor named Zi Zicheng in Weiguo. One day, Zi Gong, a student of Confucius in Paris, said, "A gentleman should have a good nature, so why should he have literary talent?" Zi Gong said, "What you said is wrong. Four horse-drawn cars can't take back what they said. Essence is as important as literary talent. Let me take fur as an example to explain! The difference between tiger leopard skin and dog sheepskin lies in its essence and literary color. If you remove the literary fur from these two kinds of skins, the skin of tiger and leopard looks like sheepskin. "

Baidu Encyclopedia-The Analects of Yan Yuan