God drove out the man; and at the east of the garden of Eden he placed the cherubim, and a sword flaming and turning to guard the way to the tree of life. (Genesis)

And the angels who did not keep their own position, but left their proper dwelling, God has kept in eternal chains in deepest darkness for the judgment of the great Day. (Jude)

It is the unique characteristic of the choir of Cherubim to possess the fullest knowledge of God.  Knowledge of God is what the Cherubim are about just as love of God is what the Seraphim are about.  It is fitting then that an angel from the choir of knowledge of God be brought into service to guard the entrance to Eden after man compromised the tree of knowledge.

Adam and Eve "wanted their eyes opened," (Genesis 3.5) meaning they wanted to possess knowledge they did not have and in fact knowledge they were expressly forbidden to seek (Genesis 2.17).  Essentially they wanted to leave the state that was proper to them and seek another, higher position.  It is no surprise that they were tempted in this way for it is precisely the way in which the angels damned themselves: "The angels who did not keep their own position, but left their proper dwelling, God has kept in eternal chains in deepest darkness for the judgment of the great Day." (Jude 6)  We can surmise that the angels in the lower choirs wanted to possess the attributes of the angles in the higher choirs instead of rejoicing in and using their own unique gifts.  Satan, being as it is thought of the Seraphim wanted to possess attributes found only in God.  Man commits a grave sin when he envies and seeks after the unique talents of others while despising and neglecting his own.  The entire creation is organized in a hierarchy to reflect God, and man must recognize and affirm the gifts of others which complement his own, while developing and using his own talents.  He is otherwise disposed to believing he can become more and more independent of his fellow man, and ultimately God.

O Lord, my heart is not proud
Nor haughty my eyes.
I have not gone after things too great
Nor marvels beyond me.

Truly I have set my soul
In silence and peace.
As a child has rest in its mother's arms,
Even so my soul.

O Israel, hope in the Lord
Both now and forever.
Psalm 131