“In short, if we are under the god of this world, away from the work and Spirit of the true God, we are held captive to his will, as Paul says to Timothy [2 Tim. 2:26], so that we cannot will anything but what he wills. For he is that strong man armed, who guards his own palace in such a way that those whom he possesses are in peace [Luke 11:21], so as to prevent them from stirring up any thought or feeling against him; otherwise, the kingdom of Satan being divided against itself would not stand [Luke 11:18], whereas Christ affirms that it does stand. And this we do readily and willingly, according to the nature of the will, which would not be a will if it were compelled; for compulsion is rather (so to say) ‘unwill.’ But if a Stronger One comes who overcomes him and takes us as His spoil, then through his Spirit we are again slaves and captives – though this is royal freedom – so that we readily will and do what he wills. Thus the human will is placed between the two like a beast of burden. If God rides it, it wills and goes where God wills, as the psalm says: ‘I am become as a beast [before thee] and I am always with thee’ [Ps. 73:22 f.]. If Satan rides it, it wills and goes where Satan wills; nor can it choose to run to either of the two riders or to seek him out, but the riders themselves contend for the possession and control of it.”

– Martin Luther, “The Bondage of the Will,” (65-66)