Who are the Angels?

Man was made lower than the angels; therefore, angels are not men.
Psa 8:4
What is man, that thou art mindful of him? and the son of man, that thou visitest him?
Psa 8:5
For thou hast made him a little lower than the angels, and hast crowned him with glory and honour.
Hebrews 2:7
Thou madest him a little lower than the angels; thou crownedst him with glory and honour, and didst set him over the works of thy hands:

Angels were made spirits.
Hebrews 1:7
And of the angels he saith, Who maketh his angels spirits, and his ministers a flame of fire.

Because they are made spirits, it does not mean that they do not have bodies.
1Cr 15:44
It is sown a natural body; it is raised a spiritual body. There is a natural body, and there is a spiritual body.
1Cr 15:45
And so it is written, The first man Adam was made a living soul; the last Adam [was made] a quickening spirit.
1Cr 15:46
Howbeit that [was] not first which is spiritual, but that which is natural; and afterward that which is spiritual.

Angels have flesh, backs, and hands. They are real, tangible bodies.
Eze 10:12
And their whole body, and their backs, and their hands, and their wings, and the wheels, [were] full of eyes round about, [even] the wheels that they four had.

They ate and drank with Lot in Sodom.
Gen 19:1
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;
Gen 19:2
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.
Gen 19:3
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.

They were sent to guard the way of the tree of life before the first man died; therefore, they are an entirely different order of beings from man.
Gen 3:22
And the LORD God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever:
Gen 3:23
Therefore the LORD God sent him forth from the garden of Eden, to till the ground from whence he was taken.
Gen 3:24
So he drove out the man; and he placed at the east of the garden of Eden Cherubims, and a flaming sword which turned every way, to keep the way of the tree of life.

While they are invisible to the naked eye, yet God has opened the eyes of even animals to see them.
Num 22:22
And God's anger was kindled because he went: and the angel of the LORD stood in the way for an adversary against him. Now he was riding upon his ass, and his two servants [were] with him.
Num 22:23
And the ass saw the angel of the LORD standing in the way, and his sword drawn in his hand: and the ass turned aside out of the way, and went into the field: and Balaam smote the ass, to turn her into the way.
Num 22:24
But the angel of the LORD stood in a path of the vineyards, a wall [being] on this side, and a wall on that side.
Num 22:25
And when the ass saw the angel of the LORD, she thrust herself unto the wall, and crushed Balaam's foot against the wall: and he smote her again.
Num 22:26
And the angel of the LORD went further, and stood in a narrow place, where [was] no way to turn either to the right hand or to the left.
Num 22:27
And when the ass saw the angel of the LORD, she fell down under Balaam: and Balaam's anger was kindled, and he smote the ass with a staff.

When God opens the eyes of men they can see the angels.
Num 22:31
Then the LORD opened the eyes of Balaam, and he saw the angel of the LORD standing in the way, and his sword drawn in his hand: and he bowed down his head, and fell flat on his face.
Num 22:32
And the angel of the LORD said unto him, Wherefore hast thou smitten thine ass these three times? behold, I went out to withstand thee, because [thy] way is perverse before me:
Num 22:33
And the ass saw me, and turned from me these three times: unless she had turned from me, surely now also I had slain thee, and saved her alive.
Num 22:34
And Balaam said unto the angel of the LORD, I have sinned; for I knew not that thou stoodest in the way against me: now therefore, if it displease thee, I will get me back again.
Num 22:35
And the angel of the LORD said unto Balaam, Go with the men: but only the word that I shall speak unto thee, that thou shalt speak. So Balaam went with the princes of Balak.

Angels are sent to communicate God’s messages to prophets.
Rev 1:1
The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants things which must shortly come to pass; and he sent and signified [it] by his angel unto his servant John:

Could men see and sense the sacredness of these messengers of God, they may very well try to worship them.
Rev 19:10
And I fell at his feet to worship him. And he said unto me, See [thou do it] not: I am thy fellowservant, and of thy brethren that have the testimony of Jesus: worship God: for the testimony of Jesus is the spirit of prophecy.

Consider this regarding strangers....
Hebrews 13:2
Be not forgetful to entertain strangers: for thereby some have entertained angels unawares.