Arminianism is the doctrine of demons

". . . The doctrines of the apostles were revived, and supernatural Theology once more lift up its head; the reformed churches published their confessions of faith, and many eminent men wrote common places, and systems of divinity; in which they all agreed in the main, to support the doctrines of revelation; as of the Trinity, and the Deity of the divine Persons in it; those of predestination and eternal election in Christ, of redemption by him, pardon of sin by his blood, and justification by his righteousness.
But Satan who envied the increasing light of the Gospel, soon began to bestir him-self, and to play his old game which he had done with so much success in the first ages of Christianity; having been for a long time otherwise engaged, to nurse up the man of sin, and to bring him to the height of his impiety and tyranny, and to support him in it: and now as his kingdom was like to be shook, if not subverted, by the doctrines of the Reformation; he, I say, goes to his old work again; and revives the Sabellian and Photinian errors, by the Socinians in Poland; and the Pelagian errors, by the Arminians and Remonstrants in Holland; the pernicious influence of which has been spread in other countries; and, indeed, has drawn a veil over the glory of the Reformation, and the doctrines of it." - John Gill, Introduction to the Body of Divinity, Pg. XXXiX