From early Christian writings until now there have been many who understood Michael to be the archangel who became Jesus on earth.
Early Christian scholar Origen writes:
"There are certain creatures, rational and divine, which are called powers [spirit creatures, probably angels]; and of these Christ was the highest and best and is called not only the wisdom of God but also His power." - ANF 10:321-322.
Back in the early 1800's, Bible scholar Joseph Benson stated that the description of Michael as found in the Bible "manifestly points out the Messiah." ……………………………
Nineteenth-century Lutheran E. W. Hengstenberg agreed that "Michael is no other than Christ."
Similarly, theologian J. P. Lange, when commenting on Revelation 12:7, wrote: "We take it that Michael . . . is, from the outset, Christ in warlike array against Satan."
Clarke’s Commentary (Adam Clarke)
“Let it be observed that the word archangel is never found in the plural number in the sacred writings. There can be properly only one archangel, one chief or head of all the angelic host. Nor is the word devil, as applied to the great enemy of mankind, ever found in the plural; there can be but one monarch of all fallen spirits. Michael is this archangel, and head of all the angelic orders; the devil, great dragon, or Satan, is head of all the diabolic orders. When these two hosts are opposed to each other they are said to act under these two chiefs, as leaders; hence in Revelation 12:7, it is said: MICHAEL and his angels fought against the DRAGON and his angels. The word Michael lakym, seems to be compounded of ym mi, who, k ke, like, and la El, God; he who is like God; hence by this personage, in the Apocalypse, many understand the Lord Jesus.”
The 1599 Geneva Study Bible: Revelation
“12:7 And there was war in heaven: 14 Michael and his angels fought against the dragon; and the dragon fought and his angels,
“(14) Christ is the Prince of angels and head of the Church, who bears that iron rod….”
John Gill, A Body of Doctrinal Divinity, Book 7 Chapter 5:
“1b2. Another prophecy in Daniel 12:1-3 respects the second and personal coming of Christ; for he is meant by Michael, who is "as God", as his name signifies, equal to him; the ‘great prince,’ the prince of the kings of the earth, and the head of all principalities and powers.”
John Gill's Exposition of the Entire Bible
And at that time shall Michael stand up,.... The Archangel, who has all the angels of heaven under him, and at his command, the Son of God, our Lord Jesus Christ;”
And even trinitarian Bible scholar W. E. Vine (“recognized as one of the world’s foremost [Bible] Greek scholars”) tells us that this “voice of the archangel” (1 Thess. 4:16) is apparently “the voice of the Lord Jesus Christ”! - p. 64, An Expository Dictionary of New Testament Words.
The International Standard Bible Encyclopaedia:
“The earlier Protestant scholars usually identified Michael with the preincarnate Christ, finding support for their view, not only in the juxtaposition of the “child” and the archangel in Rev. 12, but also in the attributes ascribed to him in Daniel” – vol. 3, p. 2048, Eerdmans Publishing, 1984 printing.
Protestant Reformer John Calvin said regarding "Michael" in its occurrence at Daniel 12:1:
"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." - J. Calvin, Commentaries On The Book Of The Prophet Daniel, trans. T. Myers (Grand Rapids: Baker Book House, 1979), vol. 2 p. 369.
A promise of deliverance, and of a joyful resurrection, ver. 1 - 4. A conference concerning the time of these events, ver. 5 - 7. An answer to Daniel's enquiry, ver. 8 - 13. For the children - The meaning seems to be, as after the death of Antiochus the Jews had some deliverance, so there will be yet a greater deliverance to the people of God, when Michael your prince, the Messiah shall appear for your salvation. A time of trouble - A the siege of Jerusalem, before the final judgment. The phrase at that time, probably includes all the time of Christ, from his first, to his last coming.
Wesley on Daniel 10:21 "Michael - Christ alone is the protector of his church, when all the princes of the earth desert or oppose it."
Jonathan Edwards (1703-1758):
Works of Jonathan Edwards, Vol. 2, Ch. 1, “Angels”:
“II. When Lucifer rebelled and set up himself as a head in opposition to God and Christ, and drew away a great number of the angels after him, Christ, the Son of God, manifested himself as an opposite head, and appeared graciously to dissuade and restrain by his grace the elect angels from hearkening to Lucifer’s temptation, so that they were upheld and preserved from eternal destruction at this time of great danger by the free and sovereign distinguishing grace of Christ. Herein Christ was the Saviour of the elect angels, for though he did not save them as he did elect men from the ruin they had already deserved, and were condemned to, and the miserable state they were already in, yet he saved them from eternal destruction they were in great danger of, and otherwise would have fallen into with the other angels. The elect angels joined with him, the glorious Michael, as their captain, while the other angels hearkened to Lucifer and joined with him, and then was that literally true that was fulfilled afterwards figuratively.
Rev. xii. ‘When there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels, and prevailed not; neither was there place found any more in heaven. And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.’ ”
William L. Alexander, Doctor of Divinity, stated:
There seems good reason for regarding Michael as the Messiah. Such was the opinion of the best among the ancient Jews.... With this all the Bible representations of Michael agree. He appears as the Great Prince who standeth for Israel (Dan. xii. I), and he is called "the Prince of Israel" (Dan. x. 21)--William L. Alexander, ed., A Cyclopedia Of Biblical Literature, originally edited by John Kitto, 3d ed. (Edinburgh: A & C Black, 1886). vol. 3, p. 158.
"The two passages in the New Testament, in which Michael is mentioned, serve to confirm the result already arrived at. That the Michael referred to in Rev. xii. 7 is no other than the Logos, [the Word - the Son of God] has already been proved in my commentary upon that passage." —Ernst Wilhelm Hengstenberg, Christology of the Old Testament and a Commentary on the Messianic Predictions, 1836-9, Vol. IV, pp. 304-5 (in the T. & T. Clark publication; p. 269 in the Kregel publication).
Brown's Dictionary of the Bible
on the words 'Michael' and 'Angel' says, that both these words do sometimes refer to Christ; and also affirms that Christ is the Archangel.
Wood's Spiritual Dictionary
teaches nearly, if not exactly, the same on this subject that Brown's does. The former was a Calvinist, the latter a Methodist.
Butterworth, Cruden, and Taylor in their concordances, assert that Michael and Angel are both names of Christ.
Guyse in his Paraphrase on the New Testament, on Rev. xii. 7, acknowledges that many good expositors think that Christ is signified by Michael; and also gives it as his opinion.
Thomas Scott, in his notes on the Bible, says the Angel that appeared to Hagar when she fled from her mistress, one of the three Angels that appeared to Abraham in the plains of Mamre, the Angel that appeared to Moses in the bush, and the Angel that spoke to the Jews at Bochim, was Jesus Christ: and also asserts that Michael the Archangel is Jesus Christ. See Gen. xvi. 9, 10. Chap. xviii throughout. Exod. iii. 2-7. Judg. ii. 1-5, Dan x. 13, 21. Chap. xii. 1, Rev. xii. 7.
Highly respected trinitarian Bible scholar, Dr. E. F. Scott, Emeritus Professor at the Union Theological Seminary, wrote:
"The author of Hebrews ... thinks of [Jesus] as an angel, whom God had exalted above all others, investing him with his own majesty and calling him by the name of Son." - p. 726, An Encyclopedia of Religion, 1945 ed.
And, again, the very trinitarian The Interpreter's Dictionary of the Bible tells us that at this time the Jewish expectation was that the Christ was
"a pre-existent, heavenly angelic being who, at the end of time, will appear at the side of God as judge of the world [see Acts 7:55-56]." - p. 364, Vol. 3, Abingdon Press, 1962.
"Angel of the Lord [angel of Jehovah] - occurs many times in the Old Testament, where in almost every instance it means a supernatural personage to be distinguished from Jehovah .... Some feel the pre-incarnate Christ is meant." - p. 39, Today's Dictionary of the Bible (trinitarian), Bethany House Publ., 1982
"Angel of the Lord. ... Christ's visible form before the incarnation." - p. 40, Smith's Bible Dictionary (trinitarian), Hendrickson Publ.
"ANGEL OF THE LORD, ... is represented in Scripture as a heavenly being sent by God to deal with men as his personal agent and spokesman [`word'] .... In the NT [which trinitarians agree explains and amplifies the OT] there is no possibility of the angel of the Lord being confused with God. .... mostly when appearing to men he is recognized as a divine being, even though in human form, and is [sometimes] addressed as God" - p. 38, New Bible Dictionary, Tyndale House (trinitarian), 1984 printing.
"The Angel of the LORD.... Traditional [from 2nd century A. D. (at least)] Christian interpretation has held that this `angel' was a preincarnate manifestation of Christ as God's Messenger-Servant. It may be ..., the angel could speak on behalf of (and so be identified with) the One [Jehovah] who sent him." - footnote for Gen. 16:7 in the highly trinitarian The NIV Study Bible by Zondervan Publishing, 1985.