Many of us tend, at least at times, to make a dichotomy between Christian doctrine and practice, as if they are opposed, rather than being a divinely ordained team, working in a beautiful, powerful harmony. Reading the Scriptures should quickly convince us otherwise. The Old Testament and the New, gospels and epistles, each part of Scripture displays in its own way the intimate, living connection between doctrine and practice. Wherever the church, by grace, prospers and flourishes, doctrine and practice are understood as inseparable.
One great, though little known, example of this is a 17th century Scottish Presbyterian work called The Sum of Saving Knowledge [c.1650]. Written by two pastors, David Dickson and James Durham, it was intended to show the connection of doctrine and practice by applying to the heart core biblical truths summarized in the Westminster Confession of Faith. In the more literate days of the 17th century this was a short read. To keep things somewhat in the realm of our bit sized blog reading I’ve included only a (relatively) small part of the second part (in somewhat updated English) of this gem here:
THE PRACTICAL USE OF SAVING KNOWLEDGE,
Contained in SCRIPTURE, and summarized in the WESTMINSTER CONFESSION of FAITH and CATECHISMS.
The chief general purpose of Christian doctrine is, to convince a man of sin, and of righteousness, and of judgment, John xvi. 8. partly by the law or covenant of works, so that he may be humbled and become repentant; and partly by the gospel or covenant of grace, that he may become a sincere believer in Jesus Christ, and be strengthened in his faith on solid grounds and reasons, and give evidence of the truth of his faith by good fruits, and so be saved.
The sum of the covenant of works, or of the law, is this: “If you do all that is commanded, and do not fail in any point, you will be saved: but if you fail, you will die.” Rom. x. 5. Gal. iii. 10, 12.
The sum of the gospel, or covenant of grace and reconciliation, is this: “If you flee from deserved wrath to the true Redeemer Jesus Christ, (who is able to fully save all who come to God through him,) you will not perish, but have eternal life.” Rom. x. 8, 9, 11.
For convincing a man of sin, of righteousness, and of judgment by the law, or covenant of works, use these scriptures, among others:
1. For convincing a man of sin by the law, consider Jer. 17:9,10.
The heart is deceitful above all things, and desperately sick; who can understand it? “I the LORD search the heart and test the mind, to give every man according to his ways, according to the fruit of his deeds.”
Here the Lord teaches these two things:
I. That the fountain of all our failure, and actual sinning against God, is in the heart, which includes the mind, will, affections, and all the powers of the soul, as they are corrupted and defiled with original sin; the mind being not only ignorant and incapable of saving truth, but also full of error and hatred against God; and the will and affections being obstinately disobedient unto all God’s directions, and bent toward that only which is evil: “The heart (he says) is deceitful above all things, and desperately wicked;” yes, and unsearchably wicked, so that no man can know it; and Gen. vi. 5. “Every imagination of the thoughts of man’s heart is only evil continually,” says the Lord, whose testimony we must trust in this and all other matters; and experience can also teach us, that, until God makes us deny ourselves, we never look to God in any thing, but fleshly self-interest alone rules us, and moves the wheels of our actions.
2. That the Lord brings our original sin, or wicked inclination, with all the actual fruits of it, to account before his judgment-seat; “For he searches the heart and test the mind, to give every man according to his ways, according to the fruit of his deeds.”
So let every man think this way:
What God and my guilty conscience bears witness of, I am convinced is true:
God and my guilty conscience bears witness, that my heart is deceitful above all things, and desperately wicked; and that all the imaginations of my heart, by nature, are only evil continually:
Therefore I am convinced that this is true.
In this way a man may be convinced of sin by the law.
II. For convincing a man of the nature of the righteousness of the law, consider Gal. iii. 10.
As many as are of the works of the law are under the curse: for it is written, Cursed is every one that continues not in all things which are written in the book of the law to do them.
Here the apostle teaches us three things:
1. That, by reason of our natural sinfulness, the impossibility of any man a being justified by the works of the law is so certain, that those who seek justification by the works of the law, are liable to the curse of God for breaking of the law: “For as many as are of the works of the law are under the curse,” saith he.
2. That, to make the requirement of perfectly fulfilling of the law, keeping of one or two of the precepts, or doing of some, or of all duties (if it were possible) for a time, is not sufficient; for the law requires, that “a man continue in all things which are written in the book of the law to do them.”
3. That, because no man can come up to this perfection, every man by nature is under the curse; for the law says, “Cursed is every one that continues not in all things which are written in the book of the law to do them.”
Now, to be under the curse, includes all the displeasure of God, with the danger of the breaking forth more and more of his wrath upon soul and body, both in this life, and after death perpetually, if grace does not prevent the full execution of this.
So let every man reason in this way:
“Whoever, according to the covenant of works, is liable to the curse of God for breaking the law, times and ways out of number, cannot be “justified, or find righteousness by the works of the law: “But I, (may every man say,) according to the covenant of works, am liable to the curse of God, for breaking the law times and ways without number:
Therefore I cannot be justified, or have righteousness by the works of the law.”
In this way a man may be convinced of righteousness, that it is not to be had by his own works, or by the law.
III. For convincing a man of judgment by the law, consider 2 Thess. i. 7.
The Lord Jesus shall be revealed from heaven with his mighty angels, Ver. 8. In flaming fire, taking vengeance on those that know not God, and that do obey not the gospel of our Lord Jesus Christ: Ver. 9. Who shall be punished with everlasting destruction from the presence of the Lord, and from, the glory of his power; Ver. 10. When he shall come to be glorified in his saints, and to be admired in all them that believe.
In this passage we are taught, that our Lord Jesus, who now offers to be Mediator for those who believe in him, will, at the last day, come armed with flaming fire, to judge, condemn, and destroy all those who have not believed God, have not received the offer of grace made in the gospel, nor obeyed the doctrine of it; but remain in their natural state, under the law or covenant of works.
So let every man reason in this way:
“What the righteous Judge has forewarned me will be done at the last day, I am sure is just judgment:
The righteous Judge has forewarned me, that if I do not believe God in time, and obey not the doctrine of the gospel, I shall be expelled from his presence and his glory at the last day, and be tormented in soul and body for ever:
Therefore I am convinced that this is a just judgment:
And I have reason to thank God heartily, who has forewarned me to flee from his coming wrath.”
In this way every man may be, by the law or covenant of works, convinced of judgment, if he continues living under the covenant of works, or refuses to obey the gospel of our Lord Jesus.
IV. For convincing a man of sin, righteousness, and judgment, by the gospel.
As for convincing a man of sin, and righteousness, and judgment, by the gospel, or covenant of grace, he must understand three things: 1. That not believing in Jesus Christ, or refusing of the covenant of grace offered in him, is a greater and more dangerous sin than all other sins against the law; because the hearers of the gospel, not believing in Christ, reject God’s mercy in Christ, the only way of freedom from sin and wrath, and refuse to yield to be reconciled to God. 2. Next, he must understand, that perfect forgiveness of sin, and true righteousness, is received only by faith in Jesus; because God requires no other conditions but faith; and testifies from heaven, that he is well pleased to justify sinners on this condition. 3. He must understand, that upon righteousness received by faith, judgment will follow, on the one hand, to the destroying of the works of the devil in the believer, and to the perfecting of the work of sanctification in him, with power: and that, on refusing to take righteousness by faith in Jesus Christ, judgment will follow, on the other hand, to the condemnation of the unbeliever, destroying him with Satan and his servants for ever.
With this goal, let these passages of scripture, among many others, serve to make the enormity of the sin of not believing in Christ evident, make the greatness of the sin of refusing of the covenant of grace offered to us, in the offering of Christ to us evident. Let the beautiful offer of grace be taken as it is made, Isa. lv. 3: Incline your ear, and come unto me, (says the Lord:) hear, and your soul will live; and I will make an everlasting covenant with you, even the sure mercies of David. That is, If you will believe me, and be reconciled to me, I will, by covenant, give Christ to you, and all saving graces in him: repeated in Acts xiii. 34.
Again, consider, that this general offer in substance is equivalent to a special offer made to every one in particular; this is clear by the apostle’s making use of it, Acts xvi. 31. Believe on the Lord Jesus Christ, and you will be saved, and your household. The reason for this offer is given, John iii. 16. For God so loved the world, that he gave his only begotten Son, that whoever believes in him should not perish, but have everlasting life. Seeing then this great salvation is offered in the Lord Jesus, whoever believes not in him, but looks for happiness some other way, what else is he doing but observing lying vanities, forsaking his own mercy, which he might have had in Christ? Jonah ii. 8, 9. What else is he doing but blaspheme God in his heart? as it is said, I John v. 10, 11. He that does not believe God has made him a liar; because he believes not the testimony that God gave of his Son. And this is the testimony, that God has given to us eternal life; and this life is in his Son. And that no sin against the law is like unto this sin, Christ testifies, John xv. 22. If I had not come and spoken to them, they would not be guilty of sin; but now they have no cover for their sin. This may convince a man of the greatness of the sin of not believing in Christ.
For convincing a man of righteousness to be had only by faith in Jesus Christ, consider how, Rom. x. 3, 4.
It is said, that the Jews, being ignorant of God’s righteousness, and going about to establish their own righteousness, have not submitted themselves unto the righteousness of God, (and so they perished.) For Christ is the end of the law for righteousness to all that believe. And Acts xiii. 39. By him all that believe are justified from all things, from which ye could not be justified by the law of Moses. And I John i. 7. The blood of Jesus Christ his Son cleanses us from all sin.
For convincing a man of judgment, if a man embraces this righteousness, consider I John iii. 8. For this purpose the Son of God was manifested, that he might destroy the works of the devil. And Heb. ix. 14. How much more shall the blood of Christ, who through the eternal Spirit offered himself without spot to God, purge your conscience from dead works to same the living God?
But if a man does not embrace this righteousness, his doom is pronounced, John iii. 18, 19. He that believes not is condemned already, because he has not believed in the name of the only begotten Son of God. And this is the condemnation, that light is come into the world, and men loved darkness rather than light.
So let the penitent, desiring to believe, reason in this way:
“What suffices to convince all the elect in the world of the greatness of the sin of not believing in Christ, or refusing to flee to him for relief from sins done against the law, and from wrath due thereto; and what suffices to convince them that righteousness and eternal life is to be bad by faith in Jesus Christ, or by consenting to the covenant of grace in him; and what suffices to convince them of judgment to be exercised by Christ, for destroying the works of the devil in a man, and sanctifying and saving all that believe in him, is enough to convince me also:
But what the Spirit has said, in these or other similar scriptures, suffices to convince the elect world of sin, and righteousness, and judgment:
Therefore what the Spirit has said, in these and other similar scriptures, serves to convince me thereof also.”
Whereupon let the penitent desiring to believe take with him words, and say heartily to the Lord, Seeing you say, Seek my face; my soul answers to you, Your face, Lord, I will seek. I have responded to the offer of an everlasting covenant of all saving mercies to be had in Christ, and I heartily embrace your offer. Lord, let it be a deal; Lord, I believe; help me in my unbelief: Behold, I give myself to you, to serve you in all things for ever; and I trust your right hand will save me: the Lord will perfect that which concerns me: your mercy, O Lord, endures for ever; forsake not the works of your own hands.
In this way a man may be made a sincere believer in Christ.”