This quote is advising us not to engage in arguments with people who are convinced that their false beliefs are true. Imagine you're talking to a friend who insists something untrue is real. It's like saying, "Don't waste your energy trying to convince someone who won't listen to reason."
Think of it as a reminder to choose your battles wisely. Just like you wouldn't try to play a game with someone who doesn't want to follow the rules, you shouldn't argue with someone who is stubbornly clinging to their own made-up version of reality.
In simpler words, the quote is telling us that some people are so convinced of their lies that arguing with them is like hitting your head against a wall. It's better to save your energy for conversations where there's a chance for understanding and growth. It's about recognizing when it's better to step away from a pointless argument and focus your time and effort on more meaningful interactions.