A word once spoken cannot be retracted even by a team of four horses.
This is from The Analects of Confucius, meaning the same as the English idiom that "A word spoken is past recalling." What is said cannot be retracted, and this is particularly true with a man of virtue who values his promise and never easily breaks it. The Chinese people often use this old adage to make a promise with sincerity.
When answering a joint interview by the press of Brazil, Russia, India, China and South Africa, or the BRICS countries, in March 2013, Xi Jinping said: China has more than once stated to the international community that it is committed to the path of peaceful development and never seeks hegemony or engages in expansion. A word once spoken cannot be retracted even by a team of four horses. History shows that China has turned its words into actions, and China hopes that other countries will all follow peaceful development and contribute to world peace and development.
君子一言，驷马难追
“君子一言，驷马难追”，出自《论语》，意为一句话说出了口，就是套上四匹马的快车也难追上。形容话已说出口，就没法再收回。也指代君子重诺，不会轻易违背自己的诺言，而中国人历来讲究以真诚之心，行信义之事。
2013年3月，习近平在接受金砖国家媒体联合采访时指出，中国已经多次向国际社会庄严承诺，将坚定不移走和平发展道路，永远不称霸，永远不搞扩张。君子一言，驷马难追，实践已经证明中国是说到做到的。中国也希望世界各国都走和平发展道路，共同致力于促进世界和平与发展。