Isaiah 14:12-15 (NKJV)
How you are fallen from heaven, O Lucifer, son of the morning! How you are cut down to the ground, You who weakened the nations!
For you have said in your heart: "I will ascend into heaven, I will exalt my throne above the stars of God; I will also sit on the mount of the congregation On the farthest sides of the north; I will ascend above the heights of the clouds, I will be like the Most High."
Yet you shall be brought down to Sheol, To the lowest depths of the Pit.
Here we have an incredible documentary of Satan's fall from heaven. Evidently, Satan was one of God's most perfect angels who had the privilege of serving in the very throne room of God as one of His guardians. But pride was his downfall. Many times great blessing and giftedness from God can be a person's downfall. Pride is the root of all sin. Those who pride themselves above God will end up in the lowest depths of the Pit.
There are five "I wills" in this verse, each attesting to Satan putting himself before God. A lot of people think they are going to heaven when they die. When I am talking to someone about Jesus, I will ask them "Why should God allow you into his heaven." Many times someone will say things like, "I try to be a good person," or "I try to keep the commandments." Of course, the purpose of such a question is to find out what is the basis of their confidence in going to heaven. But look at the answer: "I" this and "I" that. All the emphasis is on "I" and not on Him. The only way anyone is going to Heaven is to put there trust in Jesus Christ and not on themselves.