"That we being dead unto sin should live unto righteousness."--1 Peter iv. 24.
The Psalmist sings: "They go from strength to strength, every one of them in Zion appeareth before God." We must maintain this glorious testimony, altho our own experience often seems to contradict it. Not experience, but the Scripture, teaches us divine truth; nor is it as tho the procedure of the divine operation in our own heart could differ from the testimony of the Sacred Scripture, but that our experience often interprets our real spiritual condition incorrectly.
Our knowledge of self is very small. The plummet of our self-consciousness scarcely reaches below the surface, while God's holy eye penetrates the waters of the soul to the very bottom. We are ignorant of much that takes place in the soul, and what we perceive of it often presents itself to our consciousness as different from what it is in reality. If our self-knowledge were perfect, the testimony of our spiritual experience would be as reliable as that of the Scripture. But this not being so, not even among God's children, spiritual experience, tho helpful, may never weaken the Word of God. Hence, tho we discover in ourselves an ever-growing weakness, the Scripture testimony is still sure: "They go from strength to strength."
But who goes from strength to strength? Surely not the old
man. It may not be said that regeneration effected a change in him which is
constantly increasing, which enables him to make such commendable progress that
by divine help he will probably succeed in the end. This is not so. Scripture
teaches that the old man is dead, condemned to die forever; that he is
incorrigible and can not be restored, saved, or reconciled. He is hopelessly
lost. And instead of gradually becoming himself again--he must be crucified, 
slain, and buried. Instead of expecting anything good of him, it should be our
glory to die to him and be rid of him.
Neither does the new man go from strength to strength. He is not being put together little by little until he can stand on his own legs; but, since we are to live forever in the new creature, it must be a real man born in us. And as such he can not increase nor decrease; he only slumbers in the germ and must arise.
But my person, as by faith I stand in Christ, must go from strength to strength. That person was once born in the old man, and therefore was born in trespasses and sin, and is a child of wrath by nature. And he would never have come out and escaped from the old man of himself. That he could not do. He was identified with the old man so completely that the latter was his very ego. He had no other life or existence. But in regeneration a change took place. By this divine act our person is in principle detached from his former ego in the old man. The root was notched and, by the constant action of storm and gravitation, the severed parts separated more and more. Our person is no longer identified with the old man, but opposes him. Even tho he succeeds in enticing us again to sin, even in the yielding we do not what we will, but what we hate. Only hear what St. Paul says: "The good which I would I do not, but the evil which I would not that I do. Now, if I do that I would not, it is no more I that do it, but sin that dwelleth in me."
Wherefore the child of God must not be identified with the old man after regeneration, for this opposes the plain teaching of the Word. He is the old man no more, but wars against him. As God's child he is become the new man--not in part, but wholly. "Old things are passed away, behold all things are become new." In this, and nothing less, is cause of his glorying. His person is passed from death into life. He is translated from the kingdom of darkness into the kingdom of God's dear Son. He is so fully identified with the new man that, while still living in this world, he is already set with Christ in heaven, where his citizenship is, and where his life is hid with Christ in God.
If the word of the Psalmist does not refer to the old man nor
to the new, to whom, then, does it refer? The Scripture answers: to believers,
their persona, their ego, which, being detached from the old man and
opposing him, is identified with the new. They go 
from
strength to strength. It is true the use of "ego" in both senses is apt to
confuse one; yet St. Paul does the same thing. He says "I" and "not I ": "I
live, yet not I, but Christ liveth in me." The same person who fell in Adam and
out of Adam received the old man with whom for a time he was identified, is now
changed, translated, and risen with Christ; out of Christ he received a new
man, and with that new man he is being more and more identified. Hence he goes
from strength to strength.
This identification of our person with the new man is, immediately after regeneration, still very slight; while we are so thoroughly bound to the old man, with almost all the fibers of Jour being, that it seems as tho he were still our very self. But by the operation of the Holy Spirit we gradually die to the old man, and at the same time the new man is quickened in us more and more. And, since both the dying of the old and the gradual rising of the new man are profitable to our person, the Holy Spirit testifies concerning His own work that we, God's children, go from strength to strength until every one of us in Zion appeareth before God. It refers not only to our growing into the new man, but just as much to our gradual deliverance from the dying old man. In both it is the same working; hence both afford us increase of strength.
We consider first the dying of the old man as far as it relates to sanctification.
This dying has no reference to our own activity, alluded to by the office of baptism, "That we manfully fight and overcome sin and the devil and all his dominion"; on the contrary, it refers to the fruit of the cross of Christ. The question, "What further benefit do we receive from the sacrifice and death of Christ on the cross?" the Reformed Church answers: "That by virtue thereof our old man is crucified, and buried with Him; that so the corrupt inclinations of the flesh may no more reign in us" (Heidelberg Catechism, q. 4.3). Hence the dying of the old man is not the fruit of our labor; but Christ accomplishes it in us by virtue of His cross through the Holy Spirit.
In order to effect this in us the Holy Spirit diverts our personal affections, inclinations, and dispositions from the old man, to whom hitherto they have been ardently attached, so that now we begin to hate him.
It is possible for friendship to die. We may have been
intimate 
with a person whom we afterward discovered to be a
bad character. Then not only is the friendship broken, but our affection
ceases. We regret our former intimacy, and we despise him all the more
cordially as he proves to be more deceitful and malicious. And this applies to
our relation with the old man. Formerly we were most intimate with him. We
shared his will, his sympathies, and his affections. We lived one life with
him. We felt ourselves bound to him by the tenderest ties. We could not be
happy but in his company. But there came a change. We acquired a different
taste. We became acquainted with another and better man--viz., the new man in
Christ Jesus--and we became very intimate with him. And this noble intercourse
discovered to us the thorough baseness and corruption of the old man. Then our
love ceased and we began cordially to hate him.
It is true that our former connection brings us in frequent contact with him. On such occasions he often entices us by his cunning, but not to our delight; and being only half willing, our souls protest; and as soon as the sin is committed we are filled with self-loathing and contrition.
And this reversal of our affections is not our work, but that of the Holy Spirit. Not that we deny that He often uses us as instruments, or prompts us to exert ourselves, but the changing of our inclinations is not our work, but the direct operation of God the Holy Spirit.
How it is performed we can understand but partly. Essentially it is a mystery, juntas much as regeneration. Being God; the Holy Spirit has access to our heart, He discovers our personality, the nature of our affections, and in what way their action may be reversed. But our inability to fathom this mystery does not in the least affect our faith in the matter.
Since the dying of the old man is effected, not by our good works, but by the implanting of a disposition and inclination repugnant to the old man, our own work is entirely out of the question; for our own heart is inaccessible to us. We have no power over our inward person; we lack the means to create another inclination; and when w e deny this we are self-deceived. God the Creator alone can do this, and in doing it He is irresistible. Hatred against the old man, once having entered the soul, is a power that simply overwhelms us. Even when enticed by him; we can not but hate him.
The seventh chapter of Romans is very instructive in this respect. St. Paul says, "I delight in the law of God after the inward man," i.e., after my inward affections. There is indeed another law in his members, which brings him into captivity to the law of sin; but he has not the least love or sympathy for that law, but with the law of his mind wars against it.
Any other representation contradicts this positive testimony, uttered by the mouth of the most excellent of the apostles, under the seal of the Holy Spirit. He that believes embraces the Son, and can not but receive impressions and be swayed by influences that cause his affections and inclinations to become radically changed. A believer is internally wrought upon. All his former dealings with the old man--pride, hardness of heart; deceit, and thirst for revenge--now fill him with horror; what was formerly to him the pride of life and the lust of the eyes is now vexation of spirit, as he realizes how shameful and abominable it is.
So he gradually dies to the old man, until, in the hour of death, he is fully delivered. God's child remains the old man's grave-digger until the hour of his own departure.
Nevertheless he dies to him so completely that at last he loses all confidence in him, thoroughly convinced that he is without excuse, an abominable wretch, a reprobate, and a deceiver, capable of all evil. And when occasionally he indulges in scornful mirth at the old man's pride and practises, it is not in boastfulness of his own work or of his fellow men, but glorying only in the gracious work of his God.