The Holy Spirit works in the lives of believers to make them more and
more like Jesus Christ.  During this life, he “sanctifies” us, which
simply means that he makes us more holy day by day.  Romans chapter
six explains a great deal about our sanctification.

Grace is emphasized so much in the first five chapters of Romans that
some people might begin to think that God is most glorified when we
sin.  Paul says that this sort of thinking is just silly, and is
contrary to the nature of salvation.

The Christian believer is deeply united with Christ.  When Christ
died, he paid for the sins of believers completely, such that sin has
no claims on Christians.  Likewise, as Christ rose again, his victory
over death and sin assures believers that they also will have victory.
To go on sinning is to deny what Christ has done in our behalf.

Prior to being a Christian, you were subject to the power of sin.  It
was like a great king that ruled over you (6:12), a general that used
you in his wicked war (6:13), or like a slavemaster who held you in
chains.  Through Christ, you have been freed from the power of sin,
and through him, you are able to reject sin during this lifetime.