In Matthew we saw the transfiguration announced in terms that related to the subject of that Gospel-the rejected Christ taking His glorious position as Son of man. In each of the Gospels it is in connection with the moment when this transition is clearly set forth; but in each case with a particular character. In Mark we have seen the humble and devoted service of Christ in proclaiming the kingdom, whatever might be the divine glory that shone through His humiliation. Accordingly the manifestation of the transition to glory is here announced as the coming of the kingdom in power. There is nothing that very particularly distinguishes the recital here from that in Matthew, excepting that the isolation of Jesus and the three disciples at this moment is more strongly marked in verse 2, and that the facts are related without addition. The Lord afterwards charges them to tell no one what they had seen, until after His resurrection from among the dead.
We may remark here, that it is indeed the kingdom in power that is manifested. It is not the power of the Holy Ghost bringing the sinner as a holy member of the body into connection with Christ the Head, revealing to it the heavenly glory of Christ as He is at the right hand of the Father. Christ is on earth. He is there in connection with the great witnesses of the Jewish economy (the law and prophecy), but witnesses who give place entirely to Him, while participating with Him in the glory of the kingdom. But Christ is manifested in glory on the earth-the man in glory is recognised as Son of God, as He is known in the cloud. It was the glory as it shall be manifested on the earth, the glory of the kingdom, and God is still in the cloud, though revealing His glory in it. This is not our position as yet without a veil; only that the veil as to our relationship with God is rent from top to bottom, and we have boldness to enter into the holiest by the blood of Christ. But this is spiritual privilege, not public display-our veil as to that, our body, is not rent; but Christ's, as the title of entrance, is. 
But this position of glory could not be taken by the Lord, nor the glorious reign be established, excepting in a new order of things. Christ must rise from the dead to establish it. It did not accord with His presentation as Messiah, as He then was. Therefore He commands His disciples not to make it known till after His resurrection. It would then be a powerful confirmation of the doctrine of the kingdom in glory. This manifestation of the glory confirmed the faith of the disciples at that time (as Gethsemane taught them the reality of His sufferings, and of His conflicts with the prince of darkness); and would afterwards form a subject of their testimony, and its confirmation, when Christ should have taken His new position.
We may see the character of this manifestation, and its relation to the earthly kingdom of glory of which the prophets had spoken, in 2 Peter 1:19. Read there, "We have the word of prophecy confirmed."
The disciples had stopped at the threshold. In fact, although their eyes were opened, they saw "men as trees walking." What, they questioned between themselves, could this "rising from among the dead" mean? Resurrection was known to them; all the sect of the Pharisees believed in it. But this power which delivered from the condition in which man and even the saints were found, implying too that others were still left in it when that power was exercised, of this they were totally ignorant. That there was a resurrection in which God would raise up all the dead at the last day, they had no doubt. But that the Son of man was the resurrection and the life-the absolute triumph over death of the last Adam, the Son of God having life in Himself, manifested by His resurrection from among the dead (a deliverance that shall be accomplished in the saints also in due time), of this they understood nothing. Doubtless they received the Lord's words as true, as having authority; but His meaning was incomprehensible to them.
Now unbelief never fails to find out difficulties that justify it in its own eyes which refuse to perceive the divine proofs of the truth-difficulties great enough in appearance, and which may trouble the minds of those who, through grace, are inclined to believe, or who have believed, but are still weak in the faith.
The prophets had said that Elias must first come. The scribes insisted on this. Struck with the glory that undeniably confirmed the pretensions of Christ, the disciples speak to Him of this difficulty. The conviction which the sight of the glory brought to their mind, made them confess the difficulty with regard to which they had previously been silent, not daring to bring it forward. But now the proof is strong enough to embolden them to face the difficulty.
In fact, the word spoke of it, and Jesus accepts it as the truth; Elias was to come and restore all things. And he shall indeed come before the manifestation of the glory of the Son of man; but first of all the Son of man must suffer and be rejected. This also was written, as well as the mission of Elias. Moreover, before this manifestation of Christ, which tested the Jews as to their responsibility, God had not failed to supply them with a testimony according to the spirit and power of Elias; and they had ill-treated him as they listed. It was written that the Son of man should suffer before His glory, as truly as that Elias should come. However, as we have said, in point of testimony to the Jews, he who took morally the place of Elias had come. They had treated him as they were going to treat the Lord. Thus also John had said that he was not Elias, and he quotes Isaiah 40, which speaks of the testimony; but he never quotes Malachi 4, which relates to Elias personally. The Lord (Matt. 11:10) applies Malachi 3:1; but John, Isaiah.
Come down from the mountain, the people rush towards Him, astonished apparently at this mysterious absence from His disciples, and salute Him with the reverence with which His whole life had inspired them. But that which had taken place in His absence only confirmed the solemn truth that He must depart, which had just been demonstrated by a more glorious testimony. The remnant even, they who believed, knew not how to profit by the power which was now on earth. The faith of those even who believed did not realise the presence of the Messiah-the power of Jehovah, the Healer of Israel: wherefore then still remain among the people and the disciples? The poor father expresses his affliction in a touching manner, in words that shew a heart brought by the sense of its need to a right condition, but very weak in faith. The miserable state of his child is related, and his heart presents a true picture of the condition of the remnant-faith that required support on account of the unbelief under which it was buried. Israel was in no better condition than the poor child. But power was present, capable of all things. That was not the difficulty. Is there faith to profit by it? was the question. "If thou canst," said the afflicted father to Jesus. "If thou canst (replied the Lord) applies to thy faith; "if thou canst believe, all things are possible." The poor father, true of heart, confesses his own state with grief, and seeks, in the goodness of Christ, help for his failure. Thus the position of Israel was plainly shewn forth. Almighty power was present to heal them to deliver them from the power of Satan. It was to be done through faith, for the soul was to return to God. And there was faith in those who, touched by the testimony of His power, and moved by the grace of God, sought in Jesus the remedy for their woes and the foundation for their hopes. Their faith was weak and wavering; but wherever it existed, Jesus acted with the sovereign power of His own grace, and of the goodness of God that finds its measure in itself. However far unbelief may have gone in those who should profit by the grace of a dispensation, wherever there is a need to meet, Jesus answers to it when He is looked to. And this is a great mercy and encouragement for us.
Nevertheless, for this power to be exercised by man himself (to which God called him), it was needful that he should draw very near to God-that he to whom it was committed should accustom himself to communion with God, by withdrawing from all that connected him with the world and the flesh.
Let us here recapitulate the principles of this narrative with respect to their general application. The Lord, who was going away, to be seen no more of the world until He came in glory, finds, on coming down from the mount of transfiguration, a case of the power of Satan over man, over the Jewish people. It had continued from almost the commencement of the child's existence. The faith that recognises the intervention of God in Christ, and takes shelter in it from present evil, is weak and wavering, pre-occupied with the evil, the sight of which conceals in great measure the power that masters and takes it away. Still the sense of need is deep enough to make it have recourse to that power.
It is the unbelief which knows not how to count on the power that is present, which puts an end to the relations of Christ with man. It is not man's misery that does so-it was this that brought Him down to earth. But the almighty power is present-it only needs faith to profit by it. But if the heart, on account of the enemy's power, turns to Jesus, it can (thank God) bring its unbelief to Him as well as all the rest. There is love and power in Him for every kind of weakness. The people crowd around, attracted by the sight of the enemy's power. Can the Lord heal him? But can he allow the testimony of Satan's power to invade their hearts? This is the curiosity of men whose imagination is filled with the effect of the enemy's presence. But, whatever might be the unbelief of man, Christ was present, the testimony of a power that, in love to men, destroyed the effects of the power of the enemy. The people gather round-Jesus sees it, and with a word casts out the enemy. He acts according to the necessity of His power, and the purposes of the love of God. Thus the effort of the enemy occasioned the intervention of Jesus, which the weakness of the father's faith tended to arrest. Nevertheless, if we lay all our infirmity, as well as our misery, before Christ, He answers according to the fulness of His power. On the other hand, if the flesh meddles with the thoughts of faith, it hinders intelligence in the ways of God. While journeying, Christ explained His death and His new condition in resurrection. Why blame the lack of intelligence which hid all this from them, and filled their minds with ideas of earthly and Messianic glory? The secret of their want of intelligence lay here. He had told them plainly; but on the way they disputed among themselves which should have the first place in the kingdom. The thoughts of the flesh filled their heart, in regard to Jesus, with exactly the opposite of that which engaged the mind of God respecting Him. Infirmity, presented to Jesus, finds an answer in power and in sovereign grace; the flesh and its desires hide from us, even when thinking of Him, all the import of the thoughts of God. It was their own glory they were seeking in the kingdom; the cross-the true path to glory-was unintelligible to them.
After this the Lord resumes with His disciples the great subject before Him at this moment; and which was, in every way, that which now must be decided. He was to be rejected; and He separates Himself from the multitude, with His disciples, to instruct them on this point. Pre-occupied with His glory, with His rights as Messiah, they do not understand it Their faith even, such as it was, blinds them to all beyond that; because, while rightly attaching itself to the Person of Christ, it connected-or rather, their own hearts, in which the faith existed, connected-with Christ the accomplishment of that which their flesh desired and sought in Him for themselves. How subtle is the heart! This betrays itself in their dispute for pre-eminence. Their faith is too weak to bear elucidations that contradicted their ideas (v. 32). These ideas are manifested without disguise among themselves. Jesus reproves them, and gives them a little child for an example, as He had so often done before. He that would follow Christ must have a spirit quite opposite to that of the world-a spirit belonging to that which was weak and despised by the pride of the world. In receiving such a one, they would receive Christ; in receiving Christ, they would receive the Father. It was eternal things that were in question, and the spirit of a man must then be the spirit of a child.
The world was so contrary to Christ, that he who was not against Him was for Him.  The Son of man was to be rejected. Faith in His Person was the thing, not now individual service to Him. Alas! the disciples were still thinking of themselves: "He followeth not us." They must share His rejection; and if any one gave them a cup of cold water, God would remember it. Whatever would cause them to stumble in their walk, were it even their own right eye or hand, they would do well to cut off; for it was not the things of an earthly Messiah that were in question, but the things of eternity. And all should be tested by the perfect holiness of God, and that in judgment by one means or another. Every one should be salted with fire-the good and the bad. Where there was life, the fire would only consume the flesh; for when we are judged, we are chastened of the Lord, that we should not be condemned with the world. If the judgment reaches the wicked (and assuredly it shall reach them), it is condemnation-a fire that is not quenched. But, for the good, there was also something else: they should be salted with salt. Those who were consecrated to God, whose life was an offering to Him, should not lack the power of holy grace, which binds the soul to God and inwardly preserves it from evil. Salt is not the gentleness that pleases (which grace produces without doubt), but that energy of God within us which connects everything in us with God, and dedicates the heart to Him, binding it to Him in the sense of obligation and of desire, rejecting all in oneself that is contrary to Him (obligation that flows from grace, but which acts all the more powerfully on that account). Thus, practically, it was distinctive grace, the energy of holiness, which separates from all evil; but by setting apart for God. Salt was good: here the effect produced in the soul, the condition of the soul, is so called, as well as the grace that produces this condition. Thus they who offered themselves to God were set apart for Him; they were the salt of the earth. But if the salt lose its savour, wherewith can it be salted? It is used for seasoning other things; but if the salt needs it for itself, there is nothing left that can salt it. So would it be with Christians; if they who were of Christ did not render this testimony, where should anything be found, apart from Christians, to render it to them and produce it in them? Now this sense of obligation to God which separates from evil, this judgment of all evil in the heart, must be in oneself. It is not a question of judging others, but of placing oneself before God, thus becoming the salt, having it in oneself. With regard to others, one must seek peace; and real separation from all evil is that which enables us to walk in peace together.
In a word, Christians were to keep themselves separate from evil and near to God in themselves; and to walk with God in peace among one another.
No instruction could be more plain, more important, more valuable. It judges, it directs, the whole christian life in a few words.
He brings back all the relations of God with man to their original elements, setting aside the world and its glory, and Jewish glory also, as to its immediate accomplishment, and pointing out the path of eternal life in the cross, and in the saving power of God. Nevertheless He takes the place of obedience Himself, and of service-the true place of man-in the midst of all this: God Himself being introduced on the other hand, in His proper character as God, in His nature and in His divine rights; the special glory that belongs to dispensations, and the relationships proper to them, being left out.