Although we cannot see angels (except when they assume some sort of special visible form), the Bible teaches that they do exist. Not only do they exist, they exist in stupendous and incalculable numbers.
We read this again and again in the Bible, giving us some idea of the great hosts which surround the Throne of God in heaven and the great company who dwell the earth today, going forth between heaven and earth, carrying out God’s orders.
Daniel tells us in Chapter 7:

“A fiery stream issued and came forth from before him: thousand thousands ministered unto him, and ten thousand times ten thousand stood before him.” Daniel 7:10

Here we read a plain, unmistakable statement that the number of angels in heaven alone runs into countless millions. The Hebrew language had no word for million, but expressed it by saying, “a thousand thousands,” and so the expression, thousand thousands, means a million, and ten thousand times ten thousand, of course, equals one hundred million.

In the book of the Revelation we read:

“And I beheld, and I heard the voice of many angels round about the throne and the beasts and the elders: and the number of them was ten thousand times ten thousand, and thousands of thousands.” Rev. 5:11

The writer of Hebrews tells us:

“But ye are come unto Mount Sion and unto the city of the living God, the heavenly Jerusalem, and to an innumerable company of angels.” Hebrews 12:22.

This too gives us insight into the meaning of the expression often found throughout the Scripture, “The Lord of Hosts.” The word “hosts” means literally “armies,” and refers to the armies of heaven, the holy angels. In heaven, here upon earth and in the atmosphere all about us, we find this great company of spirits, unseen but real, just as real persons and creatures we know, but belonging to a different order of created beings.

How many other creatures did God create in our universe — creatures without material, physical bodies like ours, nor spiritual like the angels — we do not know, but certainly God would not limit Himself to the creation of only two classes of creatures, physical and spiritual. A thousand other forms of created beings unknown and unimaginable to us may exist, but are nevertheless know to Him and created to give to Him glory, and to do His will