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:
23 Therefore the Lord God sent him forth from the garden of Eden, to till the
ground from whence he was taken.
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.
From Wikipedia cherub is a type of spiritual being mentioned in the Hebrew Bible.
From Dictionary.com a cherub is a celestial being. Gen. 3:24; Ezek. 1, 10.
In Theology a member of the second order of angels,
In the biblical story God created the Garden of Eden with two trees; one was the
Tree of the Knowledge of Good and Evil; the other was the Tree of Life
Blake had much to say about this facet of the story; the most poignant response
he made was in The Marriage of Heaven and Hell; here's a section from Plate 14:
14 For the cherub with his flaming sword is hereby commanded to leave his
guard at the tree of life, and when he does, the whole creation will be consumed,
and appear infinite. and holy whereas it now appears finite & corrupt.
In Ezekiel 28:
 The word of the LORD came again unto me, saying,
 Son of man, say unto the prince of Tyrus, Thus saith the Lord GOD; Because thine heart
is lifted up, and thou hast said, I am a God, I sit in the seat of God, in the midst of the seas;
yet thou art a man, and not God, though thou set thine heart as the heart of God:
 Thou hast been in Eden the garden of God; every precious stone was thy covering, the
sardius, topaz, and the diamond, the beryl, the onyx, and the jasper, the sapphire, the
emerald, and the carbuncle, and gold: the workmanship of thy tabrets and of thy pipes was
prepared in thee in the day that thou wast created.
 Thou art the anointed cherub that covereth; and I have set thee so: thou wast upon the
holy mountain of God; thou hast walked up and down in the midst of the stones of fire.
 Thou wast perfect in thy ways from the day that thou wast created, till iniquity was
found in thee.
 By the multitude of thy merchandise they have filled the midst of thee with violence,
and thou hast sinned: therefore I will cast thee as profane out of the mountain of God: and I
will destroy thee, O covering cherub, from the midst of the stones of fire.
From Damon p.80:
The Cherubim of God are the spirits of understanding which are Forgiveness.
The Covering Cherub is the opposite, what we call the devil, whom God means for destroy.
Jerusalem, PLATE 89, (E 247)
"Thus was the Covering Cherub reveald majestic image
Of Selfhood, Body put off, the Antichrist accursed
Coverd with precious stones, a Human Dragon terrible
And bright, stretchd over Europe & Asia gorgeous
In three nights he devourd the rejected corse of death
His Head dark, deadly, in its Brain incloses a reflexion
Of Eden all perverted;"
Image from Rosenbach Museum, Philadelphia
Courtesy of Wikipedia
The Covering Cherub is the image which
absorbs all the error and false perceptions
which prevent man from understanding that
reentry into Eden is possible.
This image and several others like it,
including the Great Red Dragon and
the Woman clothed with the Sun.