Earlier I asserted a real difference between the Heidelberg’s approach to the question of the assurance of salvation and that of the Westminster.  There I used some quotes from John Owen to illustrate the point.

It is common in Reformed circles today to deny that there is any real difference.  At most a difference of emphasis is allowed between the two camps, but no real difference.  For some reason there seems to be a common tendency these days to gloss over the very real differences that existed on a number of topics within the Reformed world.  There was a movement for a while that’s sometimes called the “Calvin vs. the Calvinists” school that greatly exaggerated these differences, and the current trend is pushback against that I think.  But I believe they have overcorrected.  There were real differences, and this is one of them.

From John Calvin, Institutes (1541), chapter 4:

“Here then, we have a complete defiition of faith: we describe it as a firm and certain knowledge of God’s goodwill to us which, being founded on the free promise given in Jesus Christ, is revealed to our minds and sealed in our hearts by the Holy Spirit.”

…

“In short, the genuine believer is the man who, assured with firm conviction that God is a propitious and kindly Father to him looks to his goodness for all things and who, resting on the promises of his goodwill, awaits his salvation with never a doubt, even as the apostle says, “keeping faith to the end, and glorying in our hope’ (Heb. 3:6). By these words he shows that no one can truly hope in God who does not confidently boast that he is an heir of the kingdom of heaven. The genuine believer, I repeat, is the one who, relying on the assurance of his salvation, dares unflinchingly to defy the devil and death, as the apostle explains in the conclusion which he draws in Romans (Romans 8:38-39). Accordingly the apostle does not consider the eyes of our minds to be truly enlightened until we behold the hope of the eternal inheritance to which we are called. As he everywhere teaches, we do not really understand God’s goodness unless we find in it our full assurance.”

Then he goes on to address the reality of the experience of believers doubting. This he attributes to temporary failures of faith, not to the need for something to be added to faith. Faith contains assurance, he clearly teaches, but sometimes our faith is weak. So doubts arise not from the fact that assurance is something separate from faith, but from the fact that our faith is often very weak. His point throughout is that true faith includes assurance, and that all true believers will have this assurance, though at times it will waver. This is very different from WCF which teaches that assurance is a fruit of faith, not part of faith itself, and that true believers may go their whole lives without any assurance of salvation.

The Westminster position is to say that it can be true faith to believe that Jesus Christ saves sinners, but be unsure that He has saved me.  That is to say, it’s teaching that one can have true faith with no personal trust of Jesus.  They would deny this, I’m sure, but I believe it to be the clear implications of the teaching.

Zacharius Ursinus was the author of the Heidelberg Catechism.  Question 21 of that catechism says,

21. What is true faith?
True faith is not only a sure knowledge whereby I hold for truth all that God has revealed to us in His Word, but also a hearty trust, which the Holy Spirit works in me by the Gospel, that not only to others, but to me also, forgiveness of sins, everlasting righteousness, and salvation are freely given by God, merely of grace, only for the sake of Christ’s merits.

Here’s a quote from Ursinus, from his commentary on the Heidelberg Catechism, on question 21, which takes the same position on assurance as Calvin:

Justifying or saving faith differs, therefore, from the other kinds of faith, because it alone is that assured confidence by which we apply unto ourselves the merit of Christ, which is done when we firmly believe that the righteousness of Christ is granted and imputed unto us, so that we are accounted just in the sight of God.

So not only does the Heidelberg and Ursinus take the position that personal assurance of salvation is of the very nature of saving faith, but that personal assurance is chiefly that which distinguishes real faith from a temporary or merely intellectual faith.  Many people will react with joy to the Gospel, and continue in it for a time, but they have no real, personal trust in Christ, and therefore when the Gospel fails to deliver the earthly goals they crave, they fall away.

Compare this with a quote from Charles Hodge, from his Systematic Theology, part 3, chapter 16, under the subheading of assurance:

To make assurance of personal salvation essential to faith, is contrary to Scripture and to the experience of God’s people.

Hodge’s discussion in the rest of this section is quite good, though.  He attributes a want of assurance either to a weakness of faith or to bad teaching.  But of course Calvin would say the same thing- and those two things really come to the same thing, since knowledge is a component of faith.  Bad teaching leads to weak faith.  He decries the overly introspective approach of many of the Puritans:

We may examine our hearts with all the microscopic care prescribed by President [Jonathan] Edwards in his work on “The Religious Affections,” and never be satisfied that we have eliminated every ground of misgiving and doubt.  The grounds of assurance are not so much within, as without us.

Hodge does a good job then showing us the differences of approaches that exist within the Reformed world, and clearly reveals the pastoral issues at stake.  Nonetheless, because he is a Westminster man, he must maintain that assurance is not of the essence of faith, and that certainty of salvation is an “effect of faith,” not of its essence.

So there are real differences on this question within the Reformed camp, a spectrum of approaches.  We should not exaggerate those differences, but neither should we minimize them.  I myself believe that Calvin and the Heidelberg Catechism has it right, and that later in the Reformation, out of a concern over the many nominal Christians in the state churches of England and Holland, the Puritan movement developed with an intense focus on shaking people out of their complacency, challenging them on the genuineness of their faith, producing the overly introspective approach that Hodge challenges.  I think a lot of this problem, along with many others, can be laid at the feet of the existence of state churches.