The two highest states of heavenly being besides the Lord are:
Seraphim – When it is said that they are 'above the Lord' this means they are surrounding the Lord, facing the Lord, that there is no gap between them and the Lord. They cannot stand for anything to come between them and the Lord, such is the extent of their devotion. They are facing inward.
Cherubim – They are as close to the Lord as they can get other than the Seraphim, who they are standing right next to, but the Cherubim are facing outward. They are in a protective position. They are so close to the Lord they won't allow anything near the Lord that doesn’t Love the Lord, that isn’t good for the Lord. They are also known as the flaming sword.
Adam was the first being that could walk in to the Lord as a single being. Because Adam incorporated both forms, the inward facing Adam and the outward facing Eve, in a single being. Adam looks in and can see the spirit of God, nothing but the Lord in all things. Eve looks out and sees all the manifestations of creation and their many beautiful differences.
The Cherubim are saying, in effect, "“I am here to protect you.”
“From what?”
“From yourself.”
The only way you can get by the Cherubim is by loving the Lord so much that you don’t want anything else between you and the Lord. The Seraphim are in continuous Love of the Lord. So, if you do go in, and you hold that position, the Seraphim position, the Cherubim will guard you… that’s your guardian angel.
The reason for the saying that you have “an angel on each shoulder” is that you have a guardian angel on each side of you. One is holding you to a lower value, and one is holding you to a higher value. And you are positioning yourself somewhere in between them. So, your guardian angels may be 400 steps or 4000 steps away from the Lord… that all depends on your quality of Love.
When you go to visit heaven, the thing that keeps you out is your own discomfort. It is like walking in with a lump of rock in your hands called anger. And as you walk closer and closer to the Lord, it begins to get warmer, then hot, then molten, because the intensity of the Light and Love heat up anything that isn't congruent with deeper Light and Love. The Cherubim aren't trying to keep you away because they don't want you in there. They are protecting you from getting burned by yourself, or from the things you are holding on to as your reason for being in the moment.
A Proof
Sensei: "When you have had times in your life filled with negative emotion, were you guarding your heart?"
Student: "Yes."
Sensei: "That’s proof of the Cherubim. And when you aren't feeling that way, do you want someone close to your heart?"
Student: "Yes."
Sensei: "That’s proof of the Seraphim."