Of course you want to point out the error, even when it doesn't exist.<quoted text>
Sorry. You are misquoting the Bible. It is probably due to your belief in your beliefs that is the problem....One is not told to stay firm in their beliefs....That would mean one would cease to learn.
One is called to stand firm in faith in various N.T. scriptures.(1 Cor 16:13, 1 Peter 5:9) There is a major difference between faith and belief.
The confusion can come in when one does not understand the difference of to "believe in" and "believe that", as well...
"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.