Romans 8:12-13

Romans 8:12-13  Therefore, brothers and sisters, we have an obligation—but it is not to the flesh, to live according to it.  For if you live according to the flesh, you will die; but if by the Spirit you put to death the misdeeds of the body, you will live.

Paul once again points out that a Saint has an obligation to not live according to the flesh.  If anyone lives according to the flesh he will die even if he claims to believe in Christ.  It takes the indwelling Spirit for a Saint to put to death the misdeeds of the body.  Just as Christ pointed out in his description of himself as the true vine [John 15], a Saint will bear fruit, which requires remaining in Christ.  It is clear that a Saint cannot sanctify himself without the Spirit.  Therefore, the Holy Spirit is the engine that drives sanctification.  Just as there is no boasting for a person’s justification, there is also no boasting for his sanctification.