Gospel or Legal Mortification?

Editorial note: Recently I came across this very powerful tract written by the Rev. Ralph Erskine, an 18th century Presbyterian minister in the Church of Scotland. Like Warnings to the Churches, by J.C. Ryle, this tract does an excellent job delineating between true and false faith. My prayer is that this tract will be a useful tool for many within the NRC to examine their faith and ensure that it is built on a true, biblical foundation (Matthew 7:24-27). I added a few comments in brackets to help clarify some of the 18th century English.



Gospel or Legal Mortification?

by Rev. Ralph Erskine

1685 -1752

Presbyterian pastor in the Church of Scotland


“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.”

Romans 8:13 (KJV)


There is a woeful tenderness that we have of ourselves that keeps us from mortifying our corruption.  Have you never discovered or seen the evil and bitterness of sin, but lived always in peace?  Why, then it seems the strong man keeps the house [Matthew 12:29]: if the passing of the gravel stone [i.e. the small hard mass that blocks the urinary tract causing severe pain] never pained you, ye are not yet quit of it.  If your heart was never pained with sin, it says your heart was never yet circumcised.  The strength of sin remains where there has been no Gospel mortification.  Yea, what great reformations have taken place among some, so as by their life you would think they were real converts because of their exactness and tenderness.  Yet they are enemies of grace and strangers to the Gospel, and consequently to true mortification, which cannot be by the Law, it being the strength of sin.


Question: How shall I know, whether it be by the Gospel that I mortify sin or by the Law?


  1. Gospel and legal mortification differ in their principles from which they proceed.  Gospel mortification is from Gospel principles, viz., 1) the Spirit of God, “If ye through the Spirit mortify the deeds of the body, ye shall live” (Romans 8:13); 2) faith in Christ, “Purifying their hearts by faith” (Acts 15:9); and, 3) the love of Christ constraining, “The love of Christ constraineth [urges] us” (2 Corinthians 5:14).  But legal mortification is from legal principles, such as, from the applause and praise of men, as in the Pharisees; from pride and self-righteousness, as in Paul before his conversion; from the fear of hell; from a natural conscience; from the example of others; from some common promptings of the Spirit; and many times from the power of sin itself, while one sin is set up to wrestle with another, as when sensuality and self-righteousness wrestle with one another.  The man perhaps will not drink and swear:  Why?  Because he is setting up and establishing a righteousness of his own, whereby to obtain the favor of God.  Here is but one sin wrestling with another.
  2. Gospel and legal mortification differ in their weapons with which they fight against sin.  The Gospel believer fights with grace’s weapons, namely, the blood of Christ, the Word of God, the promises of the covenant, and the virtue of Christ’s death and cross.  “God forbid that I should glory, save in the cross of the Lord Jesus Christ, by whom, the world is crucified to me, and I to the world” (Galatians 6:14).  But now, the man under the Law fights against sin by the promises and threatenings of the Law: by its promises, saying, “I will obtain life and win to heaven, I hope, if I do so and so”; by its threatenings, saying, “I will go to hell and be damned, if I do not do so and so.”  Sometimes he fights with the weapons of his own vows and resolutions that are his strong tower to which he runs and thinks himself safe.
  3. They differ in the object of their mortification.  They both, indeed, seek to mortify sin: but the legalist’s quarrel is more especially with the sins of his conversation [i.e. conduct, lifestyle]; the true believer should desire to fight as the Syrians got orders, that is, neither against great nor small, so much as against the King himself, even against original corruption (2 Chronicles 18:30).  A body of sin and death troubles him more than any other sin in the world: “O wretched man that I am, who shall deliver me from this body of death?” (Romans 7:24)  His great exercise is to have the seed of the woman to bruise the head of the serpent.
  4. They differ in the reasons of the contest.  The believer, whom grace teaches to deny all ungodliness, fights against sin because it dishonors God, opposed Christ, grieves the Spirit, and separates between his Lord and him.  But the legalist fights against sin because it breaks peace, troubles his conscience, and hurts him by bringing wrath and judgment on him, as children will not play in the dust or stour [dust raised by the rapid movement of a person or thing].
  5. They differ in their motives and ends.  The believer will not serve sin because he is alive to God and dead to sin (Romans 6:6).  The legalist forsakes sin, not because he is alive, but that he may live.  The believer mortifies sin because God loves him; but the legalist, that God may love him.  The believer mortifies sin because God is pacified towards him; the legalist mortifies that he may pacify God by his mortification.  He may go a great length, but it is still that he may have whereof to glory, making his own doing all the foundation of his hope and comfort.
  6. They differ in the nature of their mortification.  The legalist does not oppose sin violently, seeking the utter destruction of it; if he can get sin put down, he does not seek it to be thrust out.  But the believer, having a nature and a principle contrary to sin, seeks not only to have it weakened, but extirpated [completely destroyed]; the quarrel is irreconcilable; no terms of accommodation or agreement; no league with sin is allowed, as it is with hypocrites.
  7. They differ in the extent of the warfare: not only objectively, the believer hating every false way; but also subjectively, all the faculties of the believer’s soul, the whole regenerate part being against sin.  It is not so with the hypocrite or legalist: as he spares some sin or other, so his opposition to sin is only seated in his conscience.  His light and conscience oppose such a thing, while his heart approves it.  There is an extent also as to time: the legalist’s opposition to sin is of short duration; but in the believer it is to the end, grace and corruption still opposing one another.
  8. They differ in the success.  There is no believer, but as he fights against sin, so first or last he prevails, though not always to his discerning.  And though he lose many battles, yet he gains the war.  But the legalist, for all the work he makes, yet he never truly comes speed [he is never truly successful]: though he cut off some actual sin, yet the corrupt nature is never changed.  He never gets a new heart.  The iron sinew in his neck, which opposes God, is never broken; and when he gets one sin mortified, sometimes another and more dangerous sin lifts up the head.  Hence, all the sins and pollutions that ever the Pharisees forsook and all the good duties that ever they performed made them but more proud and strengthened their unbelieving prejudices against Christ, which was the greater and more dangerous sin.  Thus, you may see the difference between legal and Gospel mortification and try yourselves thereby.