you can't catch the wind with a net
Proverb meaning that trying to do something impossible or futile is like trying to catch the wind with a net. Often used to describe situations where effort is wasted because the goal is unattainable.
Trying to persuade him is like trying to catch the wind with a net.
A Japanese proverb; the exact origin is uncertain, but it uses the imagery of a net's mesh being unable to hold the wind to express futility.