"But now have ye your fruit unto sanctification, and the end everlasting life."--Rom. vi, 22.
The third reason why our sanctification is in Christ is: that He has obtained it, that it flows from Him, and that He guarantees it.
Having your mind thoroughly divested from the false idea that sanctification is your own embroidery, holding fast the clear doctrine that it is a gift of grace, this third reason will appeal to you. If sanctification is a gift, a favor, the question arises: What for? Is it a reward for the labor of your soul? Fruit of your prayer? Encouragement on the way? Is it on account of your loveliness, piety, goodness? Is it for anything in you? For there must be a motive. That God should bestow the precious and enduring gift of sanctification on persons who with both hands oppose it, and with rough fingers mar its beauty, is inconceivable. What was it, then, that moved the Lord God to favor you? You say: "His unfathomable pleasure, which is the deepest ground of all our salvation." Very well; but the divine counsel does not work as by, magic. All that proceeds from that counsel runs its course, and shows its links that give it consistency.
Hence the question must be asked: "Who is it that obtained for you the gracious gift of sanctification?" And the answer is: "Our Redeemer; sanctification is the fruit of the Cross."
There is no division of labor in the redemptive work. Christ did not obtain on the cross our righteousness only; leaving it for us by conflict and self-denial to obtain our sanctification; but there is One who labors, the others enter into His rest; He has trodden the wine-press alone, and of the people there, was none with Him.
God has ordered our sanctification to flow from Christ
directly. The Holy Spirit is the Worker, yet whatever He imparts to us He 
takes from Christ. "He shall receive of Mine; and He shall glorify Me." This is
no empty phrase, but sober reality.
What a redeemed soul needs is a human holiness. A man must be sanctified, not an angel. The latter can not be sanctified. Once fallen, he is lost forever. Created and fallen like Adam; he can not be restored like Adam. Knowing nothing of redemption, angels desire to look into it. Hence when, despite sin, God brings an innumerable company of men and angels to eternal life, He effects this by sanctifying the elect among unholy men; while the elect angels need no sanctification, for they have never become unholy. Sanctification refers, therefore, exclusively to men; imparts a holiness made possible and ordained only for men; creates a disposition bearing a human form and character, calculated for the peculiar needs of the human heart.
The Holy Spirit finds this holy disposition in its required form, not in the Father, nor in Himself, but in Immanuel, who as the Son of God and the Son of, man possesses holiness in that peculiar human form.
Christ also guarantees to us this gracious gift. Justification being at once an accomplished fact does not require this; but sanctification is gradual.
The lack of such guaranty would fill us with doubt and uncertainty concerning our own sanctification, seeing that its beginning is small and progress slow; and concerning that of deceased infants and persons converted late in life. Such doubts would cause us fear and rob us of the comfort of the finished work.
Christ says: "Come unto Me, all ye that labor and are heavy-laden, and I will give you rest"; yet experience teaches that to many believers the inherent unholiness causes constant unrest. They know that in Christ they are righteous, yet they are not comforted; for God says in His Word: "Be ye holy as I am holy." If it only read, "Act holily," Christ's merits might suffice; but it reads, "Be holy," and that means inherent, holy dispositions. Or if it read, "Become holy," their gradual approach to the ideal would inspire them with hope. But it reads inexorably, "Be holy," and that causes their wounded souls to fear.
Not as tho every believer is troubled on this account.
Alas! many scarcely ever, and the large majority never, give the matter any
thought. So long as they have reconciliation and satisfaction, 
including finished
good works, preached to them, they are at rest. Their fleshly nature is
quite well satisfied with this. But there are others, more thoughtful and of
tenderer conscience, who do not accept the "wide gate and the broad way "thus
opened to their souls, but who believe the word: "Strait is the gate and narrow
the way." To them it reads; "Be holy"; and there can be no rest or
comfort for the conscience until they are reconciled with that word.
Hence we say that it is not enough that Christ has obtained sanctification, that the Holy Spirit imparts it, but also that Christ guarantees it to us, not once, but, forever; so that whenever we appear before the Holy One we may be actually holy in Christ.
And this is the blessed comfort of the Word, that Christ Himself is our sanctification. As in fallen Adam his descendants have the fearful certainty that their nature is wholly unclean, so in the risen Christ, His redeemed have the glorious guaranty that in Him they shall be completely holy.
This is the mystery of the Vine and the branches, and of the profound word: "Now are ye clean through the word which I have spoken unto you." As our Surety He assures us hereby: (i) that the holy disposition once created in us, altho temporarily overwhelmed by sin, can never be lost; (a) that Christ's form, of which there is but a small beginning in us, shall attain full perfection before we enter the New Jerusalem; (3) that as our Surety He appears before the Father in our behalf, having deposited in the treasury of His merits all that we still lack, in our name. In this knowledge the troubled soul finds rest.
Let us be careful that the precious vessel in which God presents to us this grace remains intact, for the sinner can suffice with nothing less.
But we should also be careful to avoid the other extreme,
which, under the plea that Christ is our sanctification, denies the work of the
Holy Spirit in the soul. The supporters of this view concede that Christ is our
sanctification, that the Holy Spirit works in us, and that good works are the
result, but in, such a way that our own person as such remains just as wicked
and unprofitable as heretofore. To be regenerate or not, believing or
unbelieving, is all the same. The only difference between the two is, that
independently 
of our own person, and against our will, the Holy
Spirit makes us walk unconsciously in the way of life.
This pernicious teaching opposes Rom. vii. and the Confession of the Reformed churches. The apostle does not say that his desires and inclinations are still wicked, and that the Holy Spirit performs good works independently of him and yet by him; but he grieves that, while his desire is in sympathy with the divine will and wills the good, evil is still present. In similar sense the Catechism teaches that man is inclined to all evil so long as he is not born again, but no longer. For the quickening of the new man consists in a "sincere joy of heart in God, through Christ, and with love and delight to live according to the will of God" (q. 90).
And the soul of the unconverted is not so disposed. Hence the difference between the two is so great that the gulf of heaven and hell yawns between them.
It may therefore be profitable to our readers to lay before them once more the Confession of the Reformed theologians of the churches of Switzerland, Germany, England, and the Netherlands on this point (161g).
They confessed: "That the Holy Spirit pervades the inmost recesses of the man; He opens the closed and softens the, hardened heart, and circumcises that which was uncircumcised; infuses new qualities into the will, which, tho heretofore dead, He quickens; from being evil, disobedient, and refractory, He renders it good, obedient, and pliable; actuates and strengthens it, that, like a good tree, it may bring forth the fruits of good actions" (third section, fourth Head of Doctrine, art. r 2).
And this glorious work is, according to the unanimous Confession of the Reformed churches, performed in the following manner: "That the Lord does not take away the will and its properties, neither does violence thereto; but spiritually quickens, heals, corrects, and at the same time sweetly and powerfully bends it; that where carnal rebellion and resistance formerly prevailed, a ready and sincere spiritual obedience begins to reign; in which the true and spiritual restoration and freedom of our will consist" (third section, fourth Head of Doctrine, art. r6).