Jehovah's Witnesses and Adventists claim that Michael (the angel) is Jesus. However, in the Bible Jesus is neither described as an angel nor as Michael. Not once.
They also claim that Michael is the only Archangel, which is not said in the Bible.
What is an Archangel?
There are altogether seven archangels, each of these seven angels has his own troop and the archangel is the leader of his troop. Those seven troops each have a specific task. The book of Enoch(20:1-8) gives us information about this:
And these are the names of the holy angels who watch. Uriel, one of the holy angels, who is over the world and over Tartarus. Raphael, one of the holy angels, who is over the spirits of men. Raguel, one of the holy angels who takes vengeance on the world of the luminaries. Michael, one of the holy angels, to wit, he that is set over the best part of mankind and over chaos. Saraqael, one of the holy angels, who is set over the spirits, who sin in the spirit. Gabriel, one of the holy angels, who is over Paradise and the serpents and the Cherubim. Remiel, one of the holy angels, whom God set over those who rise.
The archangels are also mentioned in the book of Tobit (12:15):
I am Raphael, one of the seven angels who stand by and enter before the glory of the Lord.
Revelation 21:9 mentions the seven angels too:
Then came one of the seven angels who had the seven bowls full of the seven last plagues and spoke to me, saying, “Come, I will show you the Bride, the wife of the Lamb.
They also claim that Michael is the only Archangel, which is not said in the Bible.
What is an Archangel?
There are altogether seven archangels, each of these seven angels has his own troop and the archangel is the leader of his troop. Those seven troops each have a specific task. The book of Enoch(20:1-8) gives us information about this:
And these are the names of the holy angels who watch. Uriel, one of the holy angels, who is over the world and over Tartarus. Raphael, one of the holy angels, who is over the spirits of men. Raguel, one of the holy angels who takes vengeance on the world of the luminaries. Michael, one of the holy angels, to wit, he that is set over the best part of mankind and over chaos. Saraqael, one of the holy angels, who is set over the spirits, who sin in the spirit. Gabriel, one of the holy angels, who is over Paradise and the serpents and the Cherubim. Remiel, one of the holy angels, whom God set over those who rise.
The archangels are also mentioned in the book of Tobit (12:15):
I am Raphael, one of the seven angels who stand by and enter before the glory of the Lord.
Revelation 21:9 mentions the seven angels too:
Then came one of the seven angels who had the seven bowls full of the seven last plagues and spoke to me, saying, “Come, I will show you the Bride, the wife of the Lamb.