From: The Bible Doctrine of God, Jesus Christ, the Holy Spirit, Atonement, Faith and Election By William Kinkade 1829
The word Michael signifies that which is like, or as God. The word Archangel is composed of two Greek words, viz., arche, a head; and angelos, a messenger. The title Michael, the Archangel, literally signifies the head messenger that is like God. This must be Jesus Christ, because we all acknowledge that he is the image of God, and the head messenger that was ever sent into our world.
I have often heard preachers speaking of Archangels in the plural, but in scripture the word is always mentioned in the singular with the definite article the before it, by which one particular personage is denoted. In fact there can be but one Archangel, that is, one head messenger, and who dare to say that Jesus Christ is not the head messenger?
If Christ is a messenger, he is an angel. If he is the head messenger, he is the Archangel. If he is like God, he is Michael ; therefore he must be Michael, the Archangel. I think every candid person that knows the meaning of these words will agree with me on this point.