Whence ariseth the imperfection of sanctification in believers?
The imperfection of sanctification in believers ariseth from the remnants of sin abiding in every part of them, and the perpetual lustings of the flesh against the spirit; whereby they are often foiled with temptations, and fall into many sins,1 are hindered in all their spiritual services,2 and their best works are imperfect and defiled in the sight of God.3
Scripture proofs
The Westminster Assembly's proof texts (KJV). The bracketed numbers in the answer above mark the clause each set of references supports; expand a row to read the verses.
1 Rom. 7:18, 23; Mark 14:66–72; Gal. 2:11–12
Rom. 7:18 For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not.
Rom. 7:23 But I see another law in my members, warring against the law of my mind, and bringing me into captivity to the law of sin which is in my members.
Mark 14:66 And as Peter was beneath in the palace, there cometh one of the maids of the high priest:
Mark 14:67 And when she saw Peter warming himself, she looked upon him, and said, And thou also wast with Jesus of Nazareth.
Mark 14:68 But he denied, saying, I know not, neither understand I what thou sayest. And he went out into the porch; and the cock crew.
Mark 14:69 And a maid saw him again, and began to say to them that stood by, This is one of them.
Mark 14:70 And he denied it again. And a little after, they that stood by said again to Peter, Surely thou art one of them: for thou art a Galilaean, and thy speech agreeth thereto.
Mark 14:71 But he began to curse and to swear, saying, I know not this man of whom ye speak.
Mark 14:72 And the second time the cock crew. And Peter called to mind the word that Jesus said unto him, Before the cock crow twice, thou shalt deny me thrice. And when he thought thereon, he wept.
Gal. 2:11 But when Peter was come to Antioch, I withstood him to the face, because he was to be blamed.
Gal. 2:12 For before that certain came from James, he did eat with the Gentiles: but when they were come, he withdrew and separated himself, fearing them which were of the circumcision.
2 Heb. 12:1
Wherefore seeing we also are compassed about with so great a cloud of witnesses, let us lay aside every weight, and the sin which doth so easily beset us, and let us run with patience the race that is set before us,
3 Isa. 64:6; Exod. 28:38
But we are all as an unclean thing, and all our righteousnesses are as filthy rags; and we all do fade as a leaf; and our iniquities, like the wind, have taken us away.
And it shall be upon Aaron’s forehead, that Aaron may bear the iniquity of the holy things, which the children of Israel shall hallow in all their holy gifts; and it shall be always upon his forehead, that they may be accepted before the LORD.
This doctrine across the Standards
Where the Confession and the Westminster Shorter Catechism treat the same matter, so the question can be studied alongside its parallel statements.
In the Westminster Confession
XIII.1 They who are effectually called and regenerated, having a new heart and a new spirit created in them, …
They who are effectually called and regenerated, having a new heart and a new spirit created in them, are further sanctified, really and personally, through the virtue of Christ's death and resurrection, by his Word and Spirit dwelling in them; the dominion of the whole body of sin is destroyed, and the several lusts thereof are more and more weakened and mortified, and they more and more quickened and strengthened, in all saving graces, to the practice of true holiness, without which no man shall see the Lord.
→ XIII.1 · Of SanctificationXIII.2 This sanctification is throughout in the whole man, yet imperfect in this life; there abideth still some remnants …
This sanctification is throughout in the whole man, yet imperfect in this life; there abideth still some remnants of corruption in every part, whence ariseth a continual and irreconcilable war, the flesh lusting against the spirit, and the spirit against the flesh.
→ XIII.2 · Of SanctificationXIII.3 In which war, although the remaining corruption for a time may much prevail, yet, through the continual supply …
In which war, although the remaining corruption for a time may much prevail, yet, through the continual supply of strength from the sanctifying Spirit of Christ, the regenerate part doth overcome; and so the saints grow in grace, perfecting holiness in the fear of God.
→ XIII.3 · Of SanctificationXVI.1 Good works are only such as God hath commanded in his holy Word, and not such as, without …
Good works are only such as God hath commanded in his holy Word, and not such as, without the warrant thereof, are devised by men out of blind zeal, or upon any pretense of good intention.
→ XVI.1 · Of Good WorksXVI.2 These good works, done in obedience to God's commandments, are the fruits and evidences of a true and …
These good works, done in obedience to God's commandments, are the fruits and evidences of a true and lively faith; and by them believers manifest their thankfulness, strengthen their assurance, edify their brethren, adorn the profession of the gospel, stop the mouths of the adversaries, and glorify God, whose workmanship they are, created in Christ Jesus thereunto, that, having their fruit unto holiness, they may have the end, eternal life.
→ XVI.2 · Of Good WorksXVI.3 Their ability to do good works is not at all of themselves, but wholly from the Spirit of …
Their ability to do good works is not at all of themselves, but wholly from the Spirit of Christ. And that they may be enabled thereunto, besides the graces they have already received, there is required an actual influence of the same Holy Spirit to work in them to will and to do of his good pleasure; yet are they not hereupon to grow negligent, as if they were not bound to perform any duty unless upon a special motion of the Spirit; but they ought to be diligent in stirring up the grace of God that is in them.
→ XVI.3 · Of Good WorksXVI.4 They who in their obedience attain to the greatest height which is possible in this life, are so …
They who in their obedience attain to the greatest height which is possible in this life, are so far from being able to supererogate and to do more than God requires, as that they fall short of much which in duty they are bound to do.
→ XVI.4 · Of Good WorksXVI.5 We cannot, by our best works, merit pardon of sin, or eternal life at the hand of God, …
We cannot, by our best works, merit pardon of sin, or eternal life at the hand of God, by reason of the great disproportion that is between them and the glory to come, and the infinite distance that is between us and God, whom by them we can neither profit nor satisfy for the debt of our former sins; but when we have done all we can, we have done but our duty, and are unprofitable servants; and because, as they are good, they proceed from his Spirit; and as they are wrought by us, they are defiled and mixed with so much weakness and imperfection that they cannot endure the severity of God's judgment.
→ XVI.5 · Of Good WorksXVI.6 Yet notwithstanding, the persons of believers being accepted through Christ, their good works also are accepted in him, …
Yet notwithstanding, the persons of believers being accepted through Christ, their good works also are accepted in him, not as though they were in this life wholly unblamable and unreprovable in God's sight; but that he, looking upon them in his Son, is pleased to accept and reward that which is sincere, although accompanied with many weaknesses and imperfections.
→ XVI.6 · Of Good WorksXVI.7 Works done by unregenerate men, although for the matter of them they may be things which God commands, …
Works done by unregenerate men, although for the matter of them they may be things which God commands, and of good use both to themselves and others; yet because they proceed not from a heart purified by faith, nor are done in a right manner, according to the Word, nor to a right end, the glory of God; they are therefore sinful, and cannot please God, or make a man meet to receive grace from God. And yet their neglect of them is more sinful and displeasing unto God.
→ XVI.7 · Of Good WorksIn the Westminster Shorter Catechism
Q.35 What is sanctification?
Sanctification is the work of God's free grace, whereby we are renewed in the whole man after the image of God, and are enabled more and more to die unto sin, and live unto righteousness.
→ Open Q.35Q.36 What are the benefits which in this life do accompany or flow from justification, adoption, and sanctification?
The benefits which in this life do accompany or flow from justification, adoption, and sanctification, are, assurance of God's love, peace of conscience, joy in the Holy Ghost, increase of grace, and perseverance therein to the end.
→ Open Q.36