一言既出，駟馬難追（一言既出，駟馬難追）　

◎ 一言既出，駟馬難追 yī yán jì chū,sìmǎ nán zhuī

[what has been said cannot be unsaid;A word spoken is past recalling; A word published cannot be recalled] 話已說出口,就是四匹馬拉的車也無法追回。形容說話要算數(shù),說出就不能收回