Ezekiel 28:15 says that Satan was perfect in his ways from the day he was created. Of course, God didn't create an evil Satan. God created a good and perfect archangel. But at a certain time, this archangel, the anointed cherub, rebelled against God.
Satan rebelled against God because of pride in his heart. Ezekiel 28:17 says that his heart was lifted up because of his beauty, that he corrupted his wisdom by reason of his brightness. He was "full of wisdom and perfect in beauty"; he "sealed up the sum," (Ezek. 28:12) meaning that he had the full measure of completeness and was short of nothing. But he gazed on his beauty and was proud. He looked at his brightness and became corrupted. To look at what God has made us and forget God Himself always tempts us to be proud. Pride was the cause of Satan's rebellion. So, the Apostle would never allow "a novice" to be an elder in the church, "lest being blinded with pride he fall into the judgment of the Devil" (1 Tim. 3:6). All the natural virtues and attributes, and all the spiritual gifts can be utilized by the Devil to make us proud. Even the Apostle Paul could be "exceedingly lifted up by the transcendence of the revelations" (2 Cor. 12:7). The proud Devil is still prowling about on the earth, seeking the proud ones whom he may devour (1 Pet. 5:8). The only way to "resist" him is to "humble" ourselves, to gird ourselves with humility because "God resists the proud, but gives grace to the humble" (1 Pet. 5:9, 5-6). The Lord Jesus is a good example in this matter. Satan exalted himself, but the Lord Jesus "humbled Himself" (Phil. 2:8). Thus, the Lord overcame Satan, and Satan had nothing in Him (John 14:30).
The purpose of Satan's rebellion was to exalt himself to be equal with God. In Isaiah 14:13-14 we find that five times Satan said "I will," at the time of his rebellion. "I will ascend..I will exalt my throne..I will sit also upon the mount..I will ascend above the heights of the clouds; I will be like the most High." Satan wanted to be equal with God. That was the purpose of his rebellion against God.
Ambition for position was the motivation of every rebellion recorded in the Bible. The rebellion at Babel (Gen. 11:4), the rebellion of Dathan, Abiram, and the two hundred and fifty princes of the Israelites (Num. 16:1-3), and the rebellion of Absalom (2 Sam. 15:10-12), were all because of the evil ambition for position. But the Lord Jesus "emptied Himself, taking the form of a slave...Wherefore also God highly exalted Him and bestowed on Him the name which is above every name" (Phil. 2:7, 9).