What does "what the morrow may not bring forth" mean? In _The Markenmore Mystery_ (1922) by J. S. Fletcher, a man was talking to a detective in a bar: > “Don’t forget, Mr. Blick—though a gentleman of your ability and experience needs no reminding of it, I’m sure—don’t forget that it’s always the unexpected that happens! The unexpected, sir!— **Ah, there’s a great deal in the unexpected!** No one knows, sir, **what the morrow may not bring forth**!” I usually find this statement in a positive form, i.e "No one know what the morrow may bring forth", but what it's meant by making it in a negative form this time?"

It's double negation — something that is not allowed in formal English, but is very common in informal English. (For example, in the _Rolling Stones_ song "I Can't Get No Satisfaction".)

What does it mean? It means exactly the same thing as the positive form would:

> No one knows what the morrow may bring forth!

Why did the author use the negative form here? I don't know. Possibly to give a more accurate representation of dialog, or possibly to give some indication as to the level of education of the speaker. It would take more context to figure this out.