Let me ask you only this: Did you receive the Spirit by works of the law or by hearing with faith? Are you so foolish? Having begun by the Spirit, are you now being perfected by the flesh?
Faith in God is inextricably linked with the fight for personal holiness. It is not the case that people are saved by grace and progressively sanctified by works, but rather, people are saved by grace through faith AND they are progressively sanctified by grace through faith.
The works that accompany one's saving faith are inextricably linked with their belief. If i believe that God is God, then that belief MUST have an impact on the way that i live my life. Not to say that sinless perfection follows a confession of faith, but rather to say that alongside belief in God is a growing knowledge of him and a growing knowledge of him is accompanied by a growing knowledge of what a terrible thing sin is.
This stands in direct contradiction to a belief that one can profess faith in God while still living in willful and persistent sin with no desire for repentance. I don't say this in an accusatory tone, but rather i say this as both a reminder/exhortation to myself and all others to seek, grow in knowledge of and to treasure the Lord.