This question already has an answer here:
If someone is saved, and they may have mistakenly or unknowingly committed blasphemy against the Holy Spirit, is his/her salvation in question? Is he/her no longer saved or welcomed in the kingdom of God?
I ask this because blasphemy is the only sin that is unforgiven.
Mark 3:29 - "But whoever blasphemes against the Holy Spirit will never be forgiven; he is guilty of an eternal sin".