The Heidelberg Catechism on True Conversion (Q/A 88-90)

Heidelberg 2True Conversion

Heidelberg Catechism Q/A 88-90 deals with one of the most crucially important topics imaginable – the nature of true conversion.

Of course, it is important to rightly understand these things, not merely in an abstract, academic way, but in a personal and experiential way. In other words, every person must essentially ask themselves, ‘Am I converted?’ and ‘How do I know if I have been converted?’

The previous question (Q/A 87) asked whether or not a person can be saved if they ‘continue in their wicked and ungrateful ways and are not converted to God.’ The answer was “By no means.”

The next few questions (Q/A 88-90) flesh out for us in more detail the nature of true conversion.

Q.88. Of how many parts does the true conversion of man consist? A. Of two parts: of the mortification of the old, and the quickening of the new man.

Q/A 88 (above) provides an outline of sorts for the next two (2) questions of the Heidelberg. Q/A 89 defines the “mortification of the old man,” and Q/A 90 defines the “quickening of the new man.”


Q.89. What is the mortification of the old man? A. It is a sincere sorrow of heart that we have provoked God by our sins, and more and more to hate and flee from them.

“Mortification” is a theological term that seems to have largely fallen out of use in our day. It was no doubt much more common when the King James Version of the Bible was the predominant translation. Consider Paul’s words in Romans 8:13 (KJV):

“For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live.” (italics added)

Newer translations, such as the ESV and others, render it simply as “put to death.”

Notice that this mortification or putting to death of our old man involves both the inner and the outer person. It includes both a “sincere sorrow of heart that we have provoked God by our sins” and a “hatred” of our sins (i.e. a changed heart), as well as fleeing from them (i.e. a changed life).

That true conversion or repentance must involve a change of heart is clear from passages such as Joel 2:12-13, which says,

“Yet even now,” declares the LORD, “return to me with all your heart, with fasting, with weeping, and with mourning; and rend your hearts and not your garments.” Return to the LORD your God, for he is gracious and merciful, slow to anger, and abounding in steadfast love; and he relents over disaster.” (ESV, Italics added)

And that true conversion must also involve a change of life is clear from passages like 2 Corinthians 7:10, where Paul writes,

“For godly grief produces a repentance that leads to salvation without regret, whereas worldly grief produces death.” (2 Corinthians 7:10, ESV)

“Godly grief” produces (or “worketh” – KJV) repentance. It results in a turning from sin unto God through faith in Christ. But “worldly grief” or sorrow, on the other hand, does not lead to repentance, and so only produces death.


Q.90. What is the quickening of the new man? A. It is a sincere joy of heart in God, through Christ, and with love and delight to live according to the will of God in all good works.

“Quickening” (or vivification – bringing to life) is the other side of the coin from mortification; both must necessarily go together.

True conversion involves not just a “sincere sorrow of heart” for our sin (Q/A 89), but also a corresponding “sincere joy of heart in God, through Christ” (Q/A 90). And it is likewise not just a turning or fleeing away from our old way of life in sin, but also a corresponding “love and delight to live according to the will of God in all good works.”

The Westminster Shorter Catechism speaks of these same things involved in true conversion as “repentance unto life”:

“Q. 87. What is repentance unto life? A. Repentance unto life is a saving grace, whereby a sinner, out of a true sense of his sin, and apprehension of the mercy of God in Christ, doth, with grief and hatred of his sin, turn from it unto God, with full purpose of, and endeavor after, new obedience.”

This is nothing less than a complete (although certainly not completed or perfected in this life) change or even reversal of orientation of a person toward sin and toward God!


And so you must ask yourself if these things are true in your own life. Have you been truly converted? Do you have a sincere sorrow of heart over your sins against God? Do you find yourself increasingly hating your sins and turning from them? (Repentance is a lifelong endeavor.)

Do you likewise have a sincere joy of heart in God through Jesus Christ, so that in love for Him you now increasingly delight to live accordingly to God’s commandments (albeit imperfectly in this life)?

Simply put, that is a description of a Christian. It is my sincere hope that this is a description of you. If so, thank God for His great love and mercy toward a sinner like you, that even when you were still dead in your sins He made you alive together with Christ and saved you by His grace!

And if that does not yet describe you, and you are not yet converted, take heed to the words of the Apostle Peter:

“Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord.” (Acts 3:19, KJV)

Repent from your sins and turn to the Lord Jesus Christ by faith – be converted! And your sins will be blotted out and forgiven!

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