Article 24: The Sanctification of Sinners from the Belgic Confession (1561) is a helpful summary of the relationship between believing the gospel of Christ and obeying the law of Christ. We can only live a life that takes the form of the cross in vertical love for God and horizontal love for others if we have been and are being transformed by the cross. The cruciform life = Love Is Faith’s Expression (Galatians 5:6).
We believe that this true faith,
produced in man by the hearing of God’s Word
and by the work of the Holy Spirit,
regenerates him and makes him a “new man,”
causing him to live the “new life”
and freeing him from the slavery of sin.
far from making people cold
toward living in a pious and holy way,
this justifying faith,
quite to the contrary,
so works within them that
apart from it
they will never do a thing out of love for God
but only out of love for themselves
and fear of being condemned.
So then, it is impossible
for this holy faith to be unfruitful in a human being,
seeing that we do not speak of an empty faith
but of what Scripture calls
“faith working through love,”
which leads a man to do by himself
the works that God has commanded
in his Word.
proceeding from the good root of faith,
are good and acceptable to God,
since they are all sanctified by his grace.
Yet they do not count toward our justification–
for by faith in Christ we are justified,
even before we do good works.
Otherwise they could not be good,
any more than the fruit of a tree could be good
if the tree is not good in the first place.
So then, we do good works,
but nor for merit-
for what would we merit?
Rather, we are indebted to God for the good works we do,
and not he to us,
since it is he who “works in us both to will and do
according to his good pleasure”
thus keeping in mind what is written:
“When you have done all that is commanded you,
then you shall say, ‘We are unworthy servants;
we have done what it was our duty to do.’ ”
Yet we do not wish to deny
that God rewards good works-
but it is by his grace
that he crowns his gifts.
although we do good works
we do not base our salvation on them;
for we cannot do any work
that is not defiled by our flesh
and also worthy of punishment.
And even if we could point to one,
memory of a single sin is enough
for God to reject that work.
So we would always be in doubt,
tossed back and forth
without any certainty,
and our poor consciences would be tormented constantly
if they did not rest on the merit
of the suffering and death of our Savior.
[Bold emphases are mine.]