I believe this is more than enough evidence to debunk the myth that this was Joseph Smith's idea, or the Jehovah's Witness'. You can find Matthew Henry's commentary in most church libraries and is still probably one of the most widely used commentaries on the bible.
You're right that the idea did not originate with SDAs or JWs or Mormons. Here is
Gill's commentary on Daniel 12:1:
The Archangel, who has all the angels of heaven under him, and at his command,
the Son of God, our Lord Jesus Christ; who is as God, as the name signifies, truly and really God, and equal in nature, power, and glory, to his divine Father: "he shall stand up"; which is not to be understood of his incarnation, or manifestation in the flesh, for this refers to times long after that; yet neither of his personal appearance in the clouds of heaven, and standing upon the earth in the latter day; but of his spiritual presence among his people, and protection of them, and continuance with them: this respects the spiritual reigns of Christ, the Lamb's standing upon Mount Zion, and the 144,000 with him, (
Revelation 14:1) , and this will be at that time, when the eastern antichrist, the Turk, will be destroyed; for the words are closely connected with the last verse of the preceding chapter; and when also the western antichrist, the pope of Rome, will come to his end; for, as they rose, so they will fall, much about the same time; and then Christ will rise and stand up, as the glorious Head of the church, and as a triumphant Conqueror over all his enemies, and take to himself his great power, and reign, and that kingdom which of right belongs to him.
Here is
Gill on Jude 9:
By whom is meant, not a created angel, but an eternal one, the Lord Jesus Christ; as appears from his name Michael, which signifies, "who is as God": and who is as God, or like unto him, but the Son of God, who is equal with God? and from his character as the archangel, or Prince of angels, for Christ is the head of all principality and power; and from what is elsewhere said of Michael, as that he is the great Prince, and on the side of the people of God, and to have angels under him, and at his command, (
Daniel 10:21) (
12:1) (
Revelation 12:7).
John Calvin also thought that Michael was Christ:
The angel no longer relates future occurrences specially, but proclaims God to be in general the guardian of his Church, so as to preserve it wonderfully amidst many difficulties and dreadful commotion’s, as well as in the profound darkness of disaster and death. This is the meaning of this sentence. This verse consists of two parts: the first relates to that most wretched period which should be full of various and almost numberless calamities; and the second assures us of God’s never-failing protection and preservation of his Church by his own innate power. In this second part the promise is restricted to the elect, and thus a third clause may be distinguished, but it is only an addition to the second just mentioned. At the close of the verse, the angel presents us with a definition of the Church, as many professed to be God’s people who were not really so. He says,
Michael, the prince of the people, should stand up Then he states the reason,
The calamities of that period should be such as were never witnessed from the beginning of the world As he addresses Daniel, he says,
sons of thy people; for he was one of the sons of Abraham, and the nation from which Daniel sprang was in that sense “his.” From this it follows that the calamities of which he will by and bye treat, belong to the true Church, and not to the profane nations. The singular aid of Michael would not have been needed, unless the Church had been oppressed with the most disastrous distresses. We perceive, then, the angel’s meaning to be according to my explanation. The Church should be subject to most numerous and grievous calamities until the advent of Christ, but yet it should feel God’s propitious disposition, ensuring its own safety under his aid and protection.
By Michael many agree in understanding Christ as the head of the Church. But if it seems better to understand Michael as the archangel, this sense will prove suitable, for under Christ as the head, angels are the guardians of the Church. Whichever be the true meaning, God was the preserver of his Church by the hand of his only-begotten Son, and because the angels are under the government of Christ, he might entrust this duty to Michael. That foul hypocrite, Servetus, has dared to appropriate this passage to himself; for he has inscribed it as a frontispiece on his horrible comments, because he was called Michael! We observe what diabolic fury has seized him, as he dared to claim as his own what is here said of the singular aid afforded by Christ; to his Church. He was a man of the most impure feelings, as we have already sufficiently made known. But this was a proof of his impudence and sacrilegious madness — to adorn himself with this epithet of Christ without, blushing, and. to elevate himself into Christ’s place, by boasting himself to be Michael, the guardian of the Church, and the mighty prince of the people! This fact is well known, for I have the book at hand should any one distrust my word. (
Commentaries on the Book of the Prophet Daniel, Vol. 2, Daniel 12:1)
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The twelfth chapter commenced, as we stated in yesterday’s Lecture, with the angel’s prediction as to the future state of the Church after the manifestation of Christ It was to be subject to many miseries, and hence this passage would soothe the sorrow of Daniel, and of all the pious, as he still promises safety to the Church through the help of God. Daniel therefore represented Michael as the guardian of the Church, and God had enjoined this duty upon Christ, as we learn from the 10th chapter of John, (
John 10:28, 29.)
As we stated yesterday, Michael may mean an angel; but I embrace the opinion of those who refer this to the person of Christ, because it suits the subject best to represent him as standing forward for the defense of his elect people. He is called the
mighty prince, because he naturally opposed the unconquered fortitude of God to those dangers to which the angel represents the Church to be subject. We well know the very slight causes for which terror often seizes our minds, and when we begin to tremble, nothing can calm our tumult and agitation. The angel then in treating of very grievous contests, and of the imminent danger of the Church, calls
Michael the mighty prince As if he had said, Michael should be the guardian and protector of the elect people, he should exercise immense power, and he alone without the slightest doubt should be sufficient for their protection. (
Commentaries on Daniel, Vol. 2, Lecture 65)
So did Charles Spurgeon:
Let the Lord Jesus Christ be for ever endeared to us, for through him we are made to sit in heavenly places far above principalities and powers. He it is whose camp is round about them that fear him;
he is the true Michael whose foot is upon the dragon. All hail, Jesus! thou Angel of Jehovah's presence, to thee this family offers its morning vows. (
Morning and Evening Devotionals, Morning, October 3)
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"Michael and his angels fought against the dragon; and the dragon fought and his angels."
- Revelation 12:7
War always will rage between the two great sovereignties until one or other be crushed. Peace between good and evil is an impossibility; the very pretence of it would, in fact, be the triumph of the powers of darkness.
Michael will always fight; his holy soul is vexed with sin, and will not endure it. Jesus will always be the dragon's foe, and that not in a quiet sense, but actively, vigorously, with full determination to exterminate evil. All his servants, whether angels in heaven or messengers on earth, will and must fight; they are born to be warriors-at the cross they enter into covenant never to make truce with evil; they are a warlike company, firm in defence and fierce in attack. The duty of every soldier in the army of the Lord is daily, with all his heart, and soul, and strength, to fight against the dragon.
The dragon and his angels will not decline the affray; they are incessant in their onslaughts, sparing no weapon, fair or foul. We are foolish to expect to serve God without opposition: the more zealous we are, the more sure are we to be assailed by the myrmidons of hell. The church may become slothful, but not so her great antagonist; his restless spirit never suffers the war to pause; he hates the woman's seed, and would fain devour the church if he could. The servants of Satan partake much of the old dragon's energy, and are usually an active race. War rages all around, and to dream of peace is dangerous and futile.
Glory be to God, we know the end of the war. The great dragon shall be cast out and for ever destroyed, while Jesus and they who are with him shall receive the crown. Let us sharpen our swords to-night, and pray the Holy Spirit to nerve our arms for the conflict. Never battle so important, never crown so glorious. Every man to his post, ye warriors of the cross, and may the Lord tread Satan under your feet shortly! (
Morning and Evening Devotionals, Evening, November 30)
Whether it's true or not, these guys were not denying the divinity of Christ by believing this. Clearly, they did not think that Michael was a created being.