To add a new difficulty to the rest, Luther is quite certain of the overwhelming power of the devil. The devil sways all men in the world to such a degree, that, although we are “lords over the devil and death,” yet “at the same time we lie under his heel ... for the world and all that belongs to it must have the devil as its master, who is far stronger than we and clings to us with all his might, for we are his guests and dwellers in a foreign hostelry.”[8] But because through faith we are masters, “my conscience, though it feels its guilt and fears and despairs on its account, yet must insist on being lord and conqueror of sin ... until sin is entirely banished and is felt no longer.”[9] Yea, since the devil is so intent on affrighting us by temptations, “we must, when tempted, banish from sight and mind the whole Decalogue with which Satan threatens and plagues us so sorely.”[10] Such advice could, however, only too easily lead people to relinquish an unequal struggle with an unquenchable Concupiscence and an overwhelmingly powerful devil, or, to lose sight of the distinction between actual sin and our mere natural concupiscence, between sin and mere temptation; Luther failed to see that his doctrines would only too readily induce an artificial confidence, and that people would put the blame for their human frailties on their lack of freedom, their ineradicable concupiscence, or on the almighty devil. How, all this notwithstanding, he contrived to turn his back on the necessary consequences of his own teaching, and to evolve a practical system of ethics far better than what his theories would have led us to expect, is plain from his warm recommendation of good works, of chastity, neighbourly love and other virtues. In brief, he taught in his own way what earlier ages had also taught, viz. that sin and vice must be shunned; in his own way he exhorted all to practise virtue, particularly to perform those deeds of brotherly charity reckoned so high in the Church of yore. In what follows we shall have to see how far his principles nevertheless intervened, and how much personal colouring he thereby imparted to his system of ethics. In so doing what we must bear in mind is his own way of viewing the aims of morality and practical matters generally, for here we are concerned, not with the results at which he should logically have arrived, but with the opinions he actually held. The difficulty of the problem is apparent not merely from the nature of certain of his theological views just stated, but particularly from what he thought concerning original sin and concupiscence, which colours most of his moral teaching.