We humans are Satan's competitors for ruling and reigning. Only we are created in God's image and ruling and reigning is our destiny and inheritance from God. The power behind the powers seeks to destroy all of us, humans.  Those who align themselves with Satan are promised all that this world has to offer from ruling and reigning now with all it's riches.
 Satan is "allowed" rulership now and can promise whatever is under his control. Those who accept his offer must deny God and fall down and worship him. He knows that eventually they will die and be gone from his kingdom, this present world, but for the moment they are useful to him.  His plan has always been to destroy what God has created and loves....humanity.
God's plan was not understood by Satan when He sent Jesus....so he killed Him with the "authority" given to him by God. But Jesus, God's own Son, resurrected  into a "New Man" into a "New Eternal  Life" and so will all who choose to follow Jesus and serve God.  Now is the time to step away from this world and fully surrender to God who Rules over ALL.
God's promises are a sure thing and will last forever!