What are angels? Popular culture has it that they are spirits of deceased humans. They are usually compelled to return to earth to perform some good deed in order to earn their wings. (For example: Clarence in "It's a Wonderful Life")

Another type of angel called a cherub, is depicted in western religious art as a chubby little naked baby with wings. Cupid with his bow and arrow would be one of these. Is this biblical? Let's meet a real cherub.

Also out of the midst thereof came the likeness of four living creatures. And this was their appearance; they had the likeness of a man. And every one had four faces, and every one had four wings. And their feet were straight feet; and the sole of their feet was like the sole of a calf's foot: and they sparkled like the colour of burnished brass. And they had the hands of a man under their wings on their four sides; and they four had their faces and their wings. Their wings were joined one to another; they turned not when they went; they went every one straight forward. As for the likeness of their faces, they four had the face of a man, and the face of a lion, on the right side: and they four had the face of an ox on the left side; they four also had the face of an eagle. Thus were their faces: and their wings were stretched upward; two wings of every one were joined one to another, and two covered their bodies. Ezekiel 1:5-11

God appears to be riding this cherub.

This is the living creature that I saw under the God of Israel by the river of Chebar; and I knew that they were the cherubim. Ezekiel 10:20

And he rode upon a cherub, and did fly: yea, he did fly upon the wings of the wind. Psalm 18:10

But angels can appear as men.

Let brotherly love continue. Be not forgetful to entertain strangers: for thereby some have entertained angels unawares. Hebrews 13:1-2

And the LORD appeared unto him in the plains of Mamre: and he sat in the tent door in the heat of the day; And he lift up his eyes and looked, and, lo, three men stood by him: and when he saw them, he ran to meet them from the tent door, and bowed himself toward the ground, And said, My Lord, if now I have found favour in thy sight, pass not away, I pray thee, from thy servant: Let a little water, I pray you, be fetched, and wash your feet, and rest yourselves under the tree: And I will fetch a morsel of bread, and comfort ye your hearts; after that ye shall pass on: for therefore are ye come to your servant. And they said, So do, as thou hast said. Genesis 18:1-5

Abraham was visited by three angels who appeared as men. Two of them went on to visit his nephew Lot. The third, I believe was the angel of the Lord. Abraham walked with them on the way to Sodom and pleaded with the angel of the Lord not to destroy the cities for the sake of the righteous people who might be living there.

And the LORD went his way, as soon as he had left communing with Abraham: and Abraham returned unto his place. Genesis 18:33

And there came two angels to Sodom at even; and Lot sat in the gate of Sodom: and Lot seeing them rose up to meet them; and he bowed himself with his face toward the ground; And he said, Behold now, my lords, turn in, I pray you, into your servant’s house, and tarry all night, and wash your feet, and ye shall rise up early, and go on your ways. And they said, Nay; but we will abide in the street all night. And he pressed upon them greatly; and they turned in unto him, and entered into his house; and he made them a feast, and did bake unleavened bread, and they did eat. Genesis 19:1-3

When God appeared to men in the past, He appeared as the angel of the Lord. Not that he became an angel, but this is how He manifested Himself visually. This is the one who later became Jesus. (Read John 1, Hebrews 1 & 2, Hebrews 8:48-58)

And the angel of the LORD appeared unto him in a flame of fire out of the midst of a bush: and he looked, and, behold, the bush burned with fire, and the bush was not consumed. Exodus 3:2

What is the purpose of angels? Angel (malak in Hebrew, aggellos in Greek) means messenger.

Are they not all ministering spirits, sent forth to minister for them who shall be heirs of salvation? Hebrews 1:14

For he shall give his angels charge over thee, to keep thee in all thy ways. Psalm 91:11

Angels are dispatched by God to protect and serve the saints. They also intervene in the affairs of the world.

And I heard a great voice out of the temple saying to the seven angels, Go your ways, and pour out the vials of the wrath of God upon the earth. Revelation 16:1

The Son of man shall send forth his angels, and they shall gather out of his kingdom all things that offend, and them which do iniquity; And shall cast them into a furnace of fire: there shall be wailing and gnashing of teeth. Matthew 13:41-42

Then who will be left behind?

Then shall the righteous shine forth as the sun in the kingdom of their Father. Who hath ears to hear, let him hear. Matthew 13:43

Angels play a very important role in the relationship between God and men, but they are not all good. Some of them are out to destroy our relationship with God. One third of the angels have become demons, and Satan is their king.

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. Revelation 12:9

And his tail drew the third part of the stars of heaven, and did cast them to the earth: and the dragon stood before the woman which was ready to be delivered, for to devour her child as soon as it was born. Revelation 12:4

And the angels which kept not their first estate, but left their own habitation, he hath reserved in everlasting chains under darkness unto the judgment of the great day. Jude 1:6

How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations! For thou hast said in thine heart, I will ascend into heaven, I will exalt my throne above the stars of God: I will sit also upon the mount of the congregation, in the sides of the north: I will ascend above the heights of the clouds; I will be like the most High. Yet thou shalt be brought down to hell, to the sides of the pit. Isaiah 14:12-15

Know ye not that we shall judge angels? how much more things that pertain to this life? I Corinthians 6:3

Angels are very powerful spirit beings who interact on behalf of God for the benefit of man and to further the cause of the kingdom of God. Demons, on the other hand, work on their own behalf for the destruction of man and to sabotage the kingdom of God. Angels and demons usually work covertly and unobtrusively but can manifest themselves visually. Humans do not become angels after death. Angels are completely separate beings from humans. They were created spirit beings from the beginning. The Bible doesn’t give us much detailed information about the spirit world. To speculate outside of what the Bible teaches is treading on dangerous ground. One third of the spirit world is demonic, so any information beyond what is scriptural is likely a lie, especially if it disagrees with scripture.