“If we believe that Satan is the Prince of this world, who constantly attacks the Kingdom of Christ with all his might and never releases the human beings he has enslaved without being forced to do so by the power of the Spirit of God, then it is clear that there can be no free-will.”[785] Either God or Satan rules over men; to this pet thought he adds: “The matter stands simply thus ... when God is in us, the devil is absent and then we can will only what is good; but when God is not there, the devil is, and then we can will only what is evil. Neither God nor Satan leaves us with an indifferent will.”[786] “When the stronger of the two comes upon us,”[787] he says, “and makes a prey of us, snatching us away from our former ruler, we become servants and prisoners to such an extent that we desire and do gladly what he wills (‘_ut velimus et faciamus libenter quæ ipse velit_’). Thus the human will stands,” Luther continues, using a simile which has become famous, “like a saddle-horse between the two. If God mounts into the saddle, man wills and goes forward as God wills ... but if the devil is the horseman, then man wills and acts as the devil wills. He has no power to run to one or the other of the two riders and offer himself to him, but the riders fight to obtain possession of the animal.”[788] With frightful boldness he declares this view to be the very core and basis of religion. Without this doctrine of the enslaved will, the supernatural character of Christianity cannot, so he says, be maintained; the work of redemption falls to the ground, because whoever sets up free-will cheats Christ of all His merit;[789] whoever advocates free-will brings death and Satan into the soul.[790] In such passages we hear the real Luther, with all his presumptuous belief in himself: “To me the defence of this truth is a matter of supreme and eternal importance. I am convinced that life itself should be set at stake in order to preserve it. It must stand though the whole world be involved thereby in strife and tumult, nay, even fall into ruins and dissolve into nothing.”[791] He ventures again to assert of Erasmus, that it had not been given him from above to feel, as he himself does, how in this great question “faith, conscience, salvation, the Word of God, the glory of Christ and even God Himself are involved.”[792] Concerning himself, on the other hand, he assures the reader that, with no earthly motives, he is waging a great war “with a God-given courage and steadfastness which his foes call obstinacy; that he holds fast to his cause in spite of so many dangers to his life, so much hatred, so many persecutions, in short, exposed as he is to the fury of man and of all the devils.”[793]