It mightily alters and changes a man!

(Thomas Brooks, "A Cabinet of Choice Jewels")

"Thanks be to God that, though you used to be
 slaves to sin — you wholeheartedly obeyed the
 form of teaching to which you were entrusted."
     Romans 6:17

Certainly, gospel-obedience is a grace of much
worth, and of great force upon the whole man;
for when it is once wrought in the heart, it works
a conformity to all God's holy will.

That obedience which springs from saving faith,
is a transforming obedience. It mightily alters
and changes a man:
  from impurity — to purity,
  from sin — to sanctity,
  from unrighteousness — to righteousness,
  from earthly-mindedness — to heavenly-mindedness,
  from pride — to humility,
  from hypocrisy — to sincerity, etc.

Those who are not savingly changed, are still
in the gall of bitterness, and bond of iniquity.