SELF is the sense of being of all creatures. It is a being's perception of its essence, reason, and importance. Self naturally is proud, selfish, and often brutish, it sees itself better than every other, it does not want to submit, sacrifice, or love except for itself, all it ever wants is to receive and not to give.

The understanding of self is inherent in every being, and so also is the perception of God.

Before the creation of the earth and the advent of man, every thing and being in heaven only had one preoccupation, the worship of God. And as they lived in obedience, they occupied their place and space, which in essence is their relevance, purpose and glory. But when a few disobeyed, they lost their place and space; they became disconnected from the life of God, and were cast out of Heaven.

“You were the anointed cherub who covers and protects, And I placed you there. You were on the holy mountain of God; You walked in the midst of the stones of fire [sparkling jewels]. You were blameless in your ways From the day you were created Until unrighteousness and evil were found in you. Through the abundance of your commerce You were internally filled with lawlessness and violence, And you sinned; Therefore I have cast you out as a profane and unholy thing From the mountain of God. And I have destroyed you, O covering cherub, From the midst of the stones of fire.”
⁃ Ezekiel‬ ‭28‬:‭14‬-‭16‬ ‭
“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 ‭KJV‬‬

In essence whenever self is not consciously seeking God, it is actually exulting itself against God. Everything created is for His worship, and worship always keeps humble, strengthens, beautifies, makes rich, and gives life.

Purpose defines the essence of every creature; ANYTHING THAT DOES NOT CONSCIOUSLY GLORIFY GOD CUTS ITSELF OFF IT'S LIFE SOURCE AND THUS BECOMES IRRELEVANT AND NEEDLESS in the grand scheme of things.

The preeminence of "self" is the only undoing of Satan, and also becomes that of every man that will not consciously seek and worship God.
This is the cardinal sin.