北ㄅㄟˇběi叟ㄙㄡˇsǒu失ㄕshī馬ㄇㄚˇmǎ

  1. 比喻世事的福禍無常，無法一時論定。參見「塞翁失馬」條。《舊唐書·卷六三·蕭瑀傳》：「應遭剖心之禍，翻見太平之日，北叟失馬，事亦難常。」

英lit. the old man lost his horse, but it all turned out for the best (idiom)​, fig. a blessing in disguise, it's an ill wind that blows nobody any good