The Bible does not state an exact number of angels, only that, to man, they seem innumerable (Hebrews 12:22). The prophet Daniel describes a dream (vision?) he had where he was given an awesome view not only of the Eternal's throne but also of the countless righteous spirits who served him.
A thousand thousands (of angels) ministered unto Him . . . (Daniel 7:10, HBFV throughout)
Taken literally, the number ten thousand multiplied by itself is one hundred million. Daniel, however, was likely using such general numeric terms to denote a group far bigger than he could count. It should also be noted that he saw only righteous angels, which make up only two-thirds of all those in existence.
There are two very broad categories of angels. The first are those who followed Lucifer's lead and, because of their rebellion against God, became demons. The Bible strongly implies that one-third of all the spirits created call the devil their leader (Revelation 12:4). The second are those who stayed loyal to God (they are considered righteous).
Scripture describes at least four special types or divisions of righteous angels - archangels, the cherubim, the seraphim, and the four living creatures. The total number of beings in the four categories likely only represent a small fraction of all obedient spirits in existence.
Michael and Gabriel are two of only three angels named in the entirety of Scripture (the other being Lucifer). Michael is specifically named as an Archangel in Jude 9. Although Gabriel is not directly referred to as in this class of beings, his involvement in major Bible events (announcing the births of Jesus and John the Baptist, directing Joseph on what to do just before and after Christ's birth, etc.) arguably puts him in this category.
The privilege of heralding the resurrection of all the dead saints who ever lived, through his voice and the sounding of a trumpet, will be given to an archangel (1Thessalonians 4:16).
Cherubim have played an interesting role throughout Biblical history. They are the first class of angels mentioning in Scripture, as they were the ones to protect the tree of life after man sinned in Eden (Genesis 3:24). It was a Cherub named Lucifer who brought sin into the universe by creating a way of life that was diametrically opposite to that of God's.
14. You were the anointed cherub that covers (covers God's glory at his throne), and I set you so . . . 15. You were perfect in your ways from the day that you were created, until iniquity (sin) was found in you . . . Therefore I will cast you as profane from the mountain of God, and I will destroy you, O covering cherub . . . (Ezekiel 28:14 - 16)
The Ark of the Covenant was built, during the time of Moses, with the wings of two Cherubs stretched over it (Exodus 25:20, 22, 37:7 - 9). A picture of these angels was also woven into the blue, purple and scarlet curtains used in Israel's wilderness tabernacle (and later the temple in Jerusalem - Exodus 26:1, 31, 36:8, 35).
Ezekiel's great "wheel in the middle of a wheel" visions, in which he was shown God's throne room, had four cherubim in it. Each of the angels had four faces - the face of a man, lion, ox and eagle (Ezekiel 1, 10).
1. In the year that King Uzziah (he was Judah's king) died, I (Isaiah) then saw the LORD sitting upon a throne . . . 2. Above it stood the seraphim; each one had six wings . . . " (Isaiah 6:1 - 3).
Other than what is revealed in Isaiah, that these types of angels were created to praise God and to act as a means of communication between the Lord and humans, not much else is known.
Four living creatures
Angels that are referred to as the "four living creatures" are only mentioned in the book of Revelation.
And around the throne and over the throne were four living creatures, full of eyes before and behind (Revelation 4:6)
Their fulltime job is to praise God and his eternal glory continually (verse 8).
Similarities and Differences
There are a few similarities, and some differences, between the appearance of the angel types of cherubim, seraphim and "living creatures."
Each of the cherubim has four wings and four faces (Ezekiel 1:6, 10:14, 21). They possess a human hand under each wing (Ezekiel 1:8, 10:8, 21). Each of them also has eyes all around their body (Ezekiel 10:12). The seraphim have six wings, not four, and seem to have only one face (Isaiah 6:2). They have hands (verse 6) although no mention is made as to how many they possess. There is no mention of them being covered with eyes. Each of the "living creatures" has six wings (Revelation 4:8) and only one face (either a lion, calf, eagle or man - verse 7) like the seraphim. Scripture, however, does not mention them having hands, although they do have eyes throughout their body (verse 6) like the cherubim.