Of course you want to point out the error, even when it doesn't exist.
"If you do not stand firm in your faith, you will not stand at all."
- as the old prophet spoke of your "God".
One can "stand firm in their belief" of "God" [aka Jesus in some eyes], but also one must stay firm in that faith of the belief.
Move past the words, and understand their meanings.
Faith is to believe what you do not see; the reward of faith is to see what you believe..(St. Augustine)
There is a difference between faith and belief. Error creeps in when one has faith in their beliefs. This is where one must be cautious.
Beliefs are based on experience and knowledge. Now knowledge may or may not be correct. And experience may be real or not real....
So for instance, a born-again Christian, that bases their faith in the experience(belief) of being born again, often finds in time that as the experience fades, so does that faith in being born-again.
Likewise, in Gnosticism, having the knowledge of enlightenment in time fades, and so enlightenment fades....
Rather it is better to have faith in God, and Jesus Christ for the forgiveness of sins, then seek knowledge and experience which yields belief....