But Luther’s inward life calls for greater sympathy.  It was after all a terrible period for him.  Close to exaltation and victory lay for him deathly anxiety, torturing doubt, and horrible apparitions.  He, almost alone, was in arms against all Christendom, and was becoming more and more irreconcilably hostile to the mightiest power, which still included everything that had been sacred to him since his youth.  What if, after all, he were wrong in this or that!  He was responsible for every soul that he led away with him—­and whither?  What was there outside the Church but destruction and perdition for time and for eternity?  If his adversaries and anxious friends cut him to the heart with reproaches and warnings, the pain, the secret remorse, the uncertainty which he must not acknowledge to any one, were greater beyond comparison.  He found peace, to be sure, in prayer.  Whenever his fervid soul, seeking its God, rose in mighty flights, he was filled with strength, peace, and cheerfulness.  But in hours of less tense exaltation, when his sensitive spirit quivered under unpleasant impressions, then he felt himself embarrassed, divided, under the spell of another power which was hostile to his God.  He knew from childhood how actively evil spirits ensnare mankind; he had learned from the Scripture that the Devil works against the purest to ruin them.  On his path the busy devils were lurking to weaken him, to mislead him, to make innumerable others wretched through him.  He saw their work in the angry bearing of the cardinal, in the scornful face of Eck, even in the thoughts of his own soul.  He knew how powerful they had been in Rome.  Even in his youth apparitions had tormented him; now they reappeared.  From the dark shadows of his study the spectre of the tempter lifted its claw-like hand against his reason.  Even while he was praying the Devil approached him in the form of the Redeemer, radiant as King of Heaven with the five wounds, as the ancient Church represented Him.  But Luther knew that Christ appears to poor humanity only in His words, or in humble form, as He hung upon the cross; and he roused himself vigorously and cried to the apparition:  “Avaunt, foul fiend!”—­and the vision disappeared.  Thus the strong heart of the man worked for years in savage indignation—­always renewed.  It was a sad struggle between reason and insanity, but Luther always came out victorious; the native strength of his sound nature prevailed.  In long prayer, often lasting for hours, the stormy waves of his emotion became calm, and his massive intelligence and his conscience brought him every time out of doubt to certainty.  He considered this process of liberation as a gracious inspiration of his God, and after such moments he who had once been in such anxious doubt was as firm as steel, indifferent to the opinion of men, not to be moved, inexorable.  Quite a different picture is that of his personality in contest with earthly foes.  Here he retains almost everywhere the superiority of conviction, particularly in his literary feuds.