What is Satan's main motive and why?

I would like to answer this question because I do believe that answer will help lot of people to remove their misunderstanding about Satan, and to stay away from him and his ways so that you may not fall into his plots. First of all, I would like to remove your misunderstanding about Satan, because many people still consider that Satan is the one person with two horns on his head and with a tail on his back, along with a back rounded face.

What Bible says through prophet Isaiah about Satan is that, Satan was an angel, A morning star, son of the dawn which is fallen from heaven, cast down to the earth, who once laid low the nations. What has happened is Satan said in his heart that, "I will ascend to heaven; I will raise my throne above the stars of God; I will sit enthroned on the mount of assembly, on the utmost heights of the sacred mountain. I will ascend above the tops of the clouds; I will make myself like the Most High." but what just happened is that, on the next moment he fall down from oldies all his heavenly glories and brought down to the grave, to the depths of the pit. God also cursed him that, those who see you stare at you, they ponder your fate: Is this the man who shook the earth and made kingdoms tremble, the man who made the world a desert, who overthrew its cities and would not let his captives go home?" All the kings of the nations lie in state, each in his own tomb. But you are cast out of your tomb like a rejected branch; you are covered with the slain, with those pierced by the sword, those who descend to the stones of the pit. Like a corpse trampled underfoot.

In Bible prophet Ezekiel gives us a detailed description about , who was Satan. It says 'Satan was the model of perfection, full of wisdom and perfect in beauty. He was in Eden, the garden of God; every precious stone adorned him: ruby, topaz and emerald, chrysolite, onyx and jasper, sapphire, turquoise and beryl. His settings and mountings were made of gold; on the day , he was created they were prepared. Satan was anointed as a guardian cherub, for so God ordained him. He was on the holy mount of God; he walked among the fiery stones.  He was blameless in your ways from the day you were created till wickedness was found in you. Through his widespread trade he was filled with violence, and he sinned. So God drove him in disgrace from the mount of God, and God expelled him, "O guardian cherub, from among the fiery stones. Your heart became proud on account of your beauty, and you corrupted your wisdom because of your splendor. So I threw you to the earth; I made a spectacle of you before kings. By your many sins and dishonest trade you have desecrated your sanctuaries. So I made a fire come out from you, and it consumed you, and I reduced you to ashes on the ground in the sight of all who were watching. All the nations who knew you are appalled at you; you have come to a horrible end and will be no more."

From this, I think you may clearly understand, who was Satan, and now it is very easy to realize and to understand the main motive of Satan. I would like to mention one more thing that human being was in God's own image and likeness after the fall of Satan. God created Adam and Eve with the power and glory more than Satan. As we can clearly see that Satan was a fallen angel, I do believe very boldly that the main motive of Satan is to make human beings also to fall from its glory and might. I can confirm it by the incident that happened in the garden of Eden where Satan lied to human being, so that he may have fall in sin and fall from the glory and grace of God.

Satan also have many other motives, which is related to the main motive, to make man falls short from the glory of God. It includes man to deviate from the commandments of God by his lies. He always tries to bring pride to human being, which is the same thing, which made him far from heaven. As a thief his main motive are to kill, steal and destroy man and his blessings.

I hope you understand very clearly the main motives of Satan. May God bless you to want in the grace of God and not too fall in these traps of Satan until the coming of Jesus Christ.