Therefore, having these promises, beloved, let us cleanse ourselves from all filthiness of the flesh and spirit, perfecting holiness in the fear of God.
We are called to cleanse ourselves of all filthiness of the flesh. This simply means that we remove it from our lives. The grace of God does not give us a license to sin or live the way we desire. The grace of God is God's unmerited favor upon our lives. We are actually called to walk according to the leading of the Holy Spirit which is contradictory to the desires of the flesh.
To continue to live according to the desires of the flesh and yet call oneself a Christian is not biblical Christianity. There are warnings about God's word about fleeing from the desires of the flesh and there is a true danger in indulging in them. When we continue to sin when we know it is wrong and we should not is to harden our heart to the Lord. The more we indulge in sin, the more our heart becomes hardened.
Once we have sinned we must repent immediately and continue to pursue God with all our heart. Jesus paid an incredible price so that we could be free from the curse of sin and death. When we claim to walk with Christ, yet continue to pursue the lust of the flesh we dishonor the sacrifice that Jesus made. May we hold fast to God's word and His promises for our lives and know in due time, He will fulfill every promise.