Pour all of the water out of (all of) the glasses.
Empty all of the glasses.
I never come across the sentences like above in my life.
If I was wrote the sentences, I would write like the following :
(1) pour all the water from the glasses.
(2) Empty all the glasses.
The original sentences has the preposition (of) in a confused manner to me.
Could you explain me in what way the preposition `of' is used here? or give me some examples with the same kind.
They're correct with 'of' and without. If you had 'none', though you would have to say 'none of the water', not 'none water'.