Oni or Japanese demon laugh?

Japanese has some interesting idioms that can be used to make your spoken language sound really good.

Today's phrase :

明日の事を言えば鬼が笑う

（あしたのことをいえばおにがわらう）

If you talk about tomorrow, a demon laughs.

What does that mean?

「あしたの事を言えば鬼が笑う」is a metaphor used to mean that we can never predict the future, so there is no point in saying this or that.

Why does a demon laugh at that?

◆ 語源　etymology :

According to one theory (and there are many theories.)

An "Oni" or Japanese demon, is thought to be a being that can see into people's future.

From the Oni's point of view, it is said that humans who are happy or sad about the future seem funny, so the demons mock them.

Certainly, we shouldn't worry too much about our future！