From "Abide in Christ" by Andrew Murray
"Of God are ye in Christ Jesus, who has made unto us wisdom from God, both righteousness and SANCTIFICATION, and redemption." I COR.1:30(R.V. marg.).
"PAUL, unto the Church of God which is at Corinth to them that are sanctified in Christ Jesus, called to be saints";--thus the chapter opens in which we are taught that Christ is our sanctification. In the Old Testament, believers were called the righteous; in the New Testament they are called saints, the holy ones, sanctified in Christ Jesus. Holy is higher than righteous. Holy in God has reference to His inmost being; righteous, to His dealings with His creatures. In man, righteousness is but a tepping-stone to holiness. It is in this he can approach most near to the perfection of God (comp. Matt.5:48; I Pet.1:16). In the Old Testament righteousness was found, while holiness was only typified; in Jesus Christ, the Holy One, and in His people, His saints or holy ones, it is first realized.
As in Scripture, and in our text, so in personal experience righteousness precedes holiness. When first the believer finds Christ as his righteousness, he has such joy in the new-made discovery that the study of holiness hardly has a place. But as he grows, the desire for holiness makes itself felt, and he seeks to know what provision his God has made for supplying that need. A superficial acquaintance with God's plan leads to the view that while justification is God's work, by faith in Christ, sanctification is our work, to be performed under the influence of the gratitude we feel for the deliverance we have experienced, and by the aid of the Holy Spirit. But the earnest Christian soon finds how little gratitude can supply the power. When he thinks that more prayer will bring it, he finds that, indispensable as prayer is, it is not enough. Often the believer struggles hopelessly for years, until he listens to the teaching of the Spirit, as He glorifies Christ again, and reveals Christ, our anctification, to be appropriated by faith alone.
Christ is made of God unto us sanctification. Holiness is the very nature of God, and that alone is holy which God takes possession of and fills with Himself. God's answer to the question, How could sinful man become holy? is, "Christ, the Holy One of God." In Him, whom the Father sanctified and sent into the world, God's holiness was revealed incarnate, and brought within reach of man. "I sanctify myself for them, that they also may be sanctified in truth." There is no other way of our becoming holy, but by becoming partakers of the holiness of Christ.  And there is no other way of this taking place than by our personal spiritual union with Him, so that through His Holy Spirit His holy life flows into us. "Of God are ye in Christ, who is made unto us sanctification." Abiding by faith in Christ our sanctification is the simple secret of a holy life. The measure of sanctification will depend on the measure of abiding in Him; as the soul learns wholly to abide in Christ, the promise is increasingly fulfilled: "The very God of peace sanctify you wholly."
To illustrate this relation between the measure of the abiding and the measure of sanctification experienced,let us think of the grafting a tree, that instructive symbol of our union to Jesus. The illustration is suggested by the Saviour's words, "Make the tree good, and his fruit good." I can graft a tree so that only a single branch bears good fruit, while many of the natural branches remain, and bear their old fruit--a type of believer in whom a small part of the life is sanctified, but in whom, from ignorance or other reasons, the carnal life still in many respects has full dominion. I can graft a tree so that every branch is cut off, and the whole tree becomes renewed to bear good fruit; and yet, unless I watch over the tendency of the stems to give sprouts, they may again rise and grow strong, and, robbing the new graft of the strength it needs, make it weak. Such are Christians who, when apparently powerfully converted, forsake all to follow Christ, and yet after a time, through unwatchfulness, allow old habits to regain their power, and whose Christian life and fruit are but feeble. But if I want a tree wholly made good, I take it when young, and, cutting the stem clean off on the ground, I graft it just where it emerges from the soil. I watch over every bud which the old nature could possibly put forth, until the flow of sap from the old roots into the new stem is so complete, that the old life has, as it were, been entirely conquered and covered by the new. Here I have a tree entirely renewed--emblem of the Christian who has learnt in entire consecration to surrender everything for Christ, and in a whole-hearted faith wholly to abide in Him.
If, in this last case, the old tree were a reasonable being that could co-operate with the gardener, what would his language be to it? Would it not be this: "Yield now yourself entirely to this new nature with which I have invested you; repress every tendency of the old nature to give buds or sprouts; let all your sap and all your life-powers rise up into this graft from yonder beautiful tree, which I have put on you; so shall you bring forth sweet and much fruit." And the language of the tree to the gardener would be: "When you graft me, O spare not a single branch; let everything of the old self, even the smallest bud, be destroyed, that I may no longer live in my own, but in that other life that was cut off and brought and put upon me, that I might be wholly new and good." And, once again, could you afterwards ask the renewed tree, as it was bearing abundant fruit, what it could say of itself, its answer would be this: "In me, that is, in my roots, there dwells no good thing. I am ever inclined to evil; the sap I collect from the soil is in its nature corrupt, and ready to show itself in bearing evil fruit. But just when the sap rises into the sunshine to ripen into fruit, the wise gardener has clothed me with a new life, through which my sap is purified, and all my powers are renewed to the bringing forth of good fruit. I have only to abide in that which I have received. He cares for the immediate repression and removal of every bud which the old nature still would
Christian, fear not to claim God's promises to make you holy. Listen not to the suggestion that the corruption of your old nature would render holiness an impossibility. In your flesh dwells no good thing, and that flesh, though crucified with Christ, is not yet dead, but will continually seek to rise and lead you to evil. But the Father is the Husbandman. He has grafted the life of Christ on your life. That holy life is mightier than your evil life; under the watchful care of the Husbandman, that new life can keep down the workings of the evil life within you. The evil nature is there, with its unchanged tendency to rise up and show itself. But the new nature is there too--the living Christ, your sanctification, is there--and through Him all your powers can be sanctified as they rise into life, and be made to bear fruit to the glory of the Father.
And now, if you would live a holy life, abide in Christ your sanctification. Look upon Him as the Holy One of God, made man that He might communicate to us the holiness of God. Listen when Scripture teaches that there is within you a new nature, a new man, created in Christ Jesus in righteousness and true holiness. Remember that this holy nature which is in you is singularly fitted for living a holy life, and performing all holy duties, as much so as the old nature is for doing evil. Understand that this holy nature within you has its root and life in Christ in heaven, and can only grow and become strong as the intercourse between it and its source is uninterrupted. And above all, believe most confidently that Jesus Christ Himself delights in maintaining that new nature within you, and imparting to it His own strength and wisdom for its work. Let that faith lead you daily to the surrender of all self-confidence, and the confession of the utter corruption of all there is in you by nature. Let it fill you with a quiet and assured confidence that you are indeed able to do what the Father expects of you as His child, under the covenant of His grace, because you have Christ strengthening you. Let it teach you to lay yourself and your services on the altar as spiritual sacrifices, holy and acceptable in His sight, a sweet-smelling savour. Look not upon a life of holiness as a strain and an effort, but as the natural outgrowth of the life of Christ within you. And let ever again a quiet, hopeful, gladsome faith hold itself assured that all you need for a holy life will most assuredly be given you out of the holiness of Jesus. Thus will you understand and prove what it is to abide in Christ our sanctification.
The thought that in the personal holiness of our Lord a new holy nature was formed to be communicated to us, and that we make use of it by faith, is the central idea of Marshall's invaluable work, The Gospel Mystery of Sanctcation:
"One great mystery is, that the holy frame and disposition whereby our souls are furnished and enabled for immediate practice of the law, must be obtained by receiving it out of Christ's fulness, as a thing already prepared and brought to an existence for us in Christ, and treasured up in Him; and that, as we are justified by a righteousness wrought out in Christ, and imputed to us, so we are sanctified by such an holy frame and qualification as are first wrought out and completed in Christ for us, and then imparted to us. As our natural corruption was produced originally in the first Adam, and propagated from him to us, so our new nature and holiness is first produced in Christ, and derived from Him to us, or, as it were, propagated. So that we are not at all to work together with Christ in making or producing that holy frame in us, but only to take it to ourselves, and use it in our holy practice, as made ready to our hands. Thus we have fellowship with Christ, in receiving that holy frame of spirit that was originally in Him; for fellowship is where several persons have the same things in common. This mystery is so great, that notwithstanding all the light of the Gospel, we commonly think that we must get an holy frame by producing it anew in ourselves, and by pursuing it and working it out of our own heart" (see chap. 3). 
1. "Holiness may be called spiritual perection, as righteousnes is legal completeness." --Horatius Bonar in God's Way of Holiness.
2. See note at end of chapter.
3. I have felt so strongly that the teaching of Marshall is just what the Church needs to bring out clearly what the Scripture path of holiness is, that I have prepared an abridgment (all in the author's own words) of his work. By leaving out what was not essential to his argument, and shortening when he appeared diffuse, I hoped to bring his book within reach of many who might never read the larger work. It is published by Nisbet & Co. under the title, The Highway of Holiness. I cannot too earnestly urge every student of theology, and of Scripture, and of the art of holy living, to make himself master of the teaching of Marshall's third, fourth, and twelfth chapters.
Publisher's Note: The original complete work, The Gospel Mystery of Sanctification, was reissued by Oliphants Ltd. in 1955.