Ministers will be judged by God on the grounds of criminal negligence who allow their church members to continue in their sinful habits and at the same time believe they are gloriously saved. The Apostle Paul used the future tense, shalt be, which places the act or event in the future. You do not have faith if you do not have works. Faith without works is dead. It can not save you if it is alone.
Works are proof of faith.
If works prove faith, then the absence of works prove unbelief. Yes, faith is necessary to be saved, but it takes more than just faith. He believed but was still unsaved. Even Simon Peter himself believed and made a confession of faith in Matt. The Bible teaches he was not.