Why will Satan fight?

There are many who think this verse is key...

13 Thou hast been in Eden the garden of God;

If you go back to the Genesis account you will find 3 entities in the garden. God, Man and the evil temptor. I guess this could be man. Look closely at vs 14 & 15. I don't know if man was ever referred to as a cherub and we are said to be a little lower than the angels though in another thread that word is being defined as god (little G). so you could be right. Now compare Exek with this quote from Isaiah which was credited to Lucifer. Note some similarities.

Isa 14:12 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!
13 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:
14 I will ascend above the heights of the clouds; I will be like the most High.
15 Yet thou shalt be brought down to hell, to the sides of the pit.

 

At Bible.org you will find this article which is an extensive treatment of The Doctrine of Angels.

 

Good read... I like this part.

The Division of Angels—Good and Evil
While all the angels were originally created holy and without sin, there was a rebellion by Satan, who, being lifted up by his own beauty, rebelled and sought to exalt himself above God. In his rebellion, he took with him one-third of the angels (Rev. 12:4). This rebellion and fall is probably described for us in Isaiah 14:12-15 and Ezekiel 28:15 embodied in the kings of Babylon and Tyre.22 Prophesying of a future angelic conflict that will occur in the middle of the Tribulation, John wrote, “And there was war in heaven, Michael and his angels waging war with the dragon. And the dragon and his angels waged war” (Rev. 12:7). In other words, there are good angels and there are evil angels. Regarding their fall, Bushwell writes:

We infer that the angels which sinned did so in full knowledge of all the issues involved. They chose self-corruption, knowing exactly what they were doing. They sinned without remedy, and there is no atonement for them (II Peter 2:4; Jude 6). On the other hand, it seems that the holy angels, being faced with the same ethical choice and possessing the same God-given ability to choose, remained and are confirmed in their state of holiness. They have never known the experience of sin.23

As is clear from Revelation 12:7 and many other passages, the leader of these fallen angels, or demons as they are also called, is Satan (cf. Matt. 12:25-27). As the leader of these unholy angels, Satan is a liar, a murderer, and a thief (John 10:10). As God’s great antagonist, Satan hates God and His people and is constantly on the prowl like a roaring lion in search of those he may devour by his nefarious schemes (1 Peter 5:8). As an angelic being, Satan, along with his demon-like angels, is supernaturally powerfully and brilliant, and uses all his powers against humanity. Not only is he a liar, a thief, and a distorer, but one of his chief characterizations is deception. John describes him as the one “who deceives the whole world” (John 12:9). In his cunning, he disguises himself as an angel of light (2 Cor. 11:14). In view of this, the Apostle Paul wrote, “Therefore it is not surprising if his servants also disguise themselves as servants of righteousness …” (2 Cor. 11:15).

 

And yet it's funny how satan can do nothing without God's permission.

Luke 22:31 And the Lord said, “Simon, Simon! Indeed, Satan has asked for you, that he may sift you as wheat.

Asked? Why did satan need to ask?