běi sǒu shī mǎ

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

【释义】比喻祸福没有一定。

【近义】塞翁失马

【出处】《旧唐书·萧瑀传》：“应遭剖心之祸，翻见太平之日，北叟失马，事亦难常。”