Catholic writers assert that the doctrine which we have just outlined is not Scriptural, but represents the grossest perversion of Scripture. They say this doctrine originated in "the erratic brain of Luther." Luther "was not an exact thinker, and being unable to analyze an idea into its constituents, as is necessary for one who will apprehend it correctly, he failed to grasp questions which by the general mass of the people were thoroughly and correctly understood. . . . He allowed himself to cultivate an unnecessary antipathy to so-called 'holiness by works,' and this attitude, combined with his tendency to look at the worst side of things, and his knowledge of some real abuses then prevalent in the practise of works, doubtless contributed to develop his dislike for good works in general, and led him by degrees to strike at the very roots of the Catholic system of sacraments and grace, of penance and satisfaction, in fact, all the instruments or means instituted by God both for conferring and increasing His saving relationship with man." Luther's teaching on justification is said to be the inevitable reverse of his former self-exaltation. Abandoning the indispensable virtue of humility, he had become a prey to spiritual pride, and had entered the monastery to achieve perfect righteousness by his own works. He had disregarded the wise counsels of his brethren, who had warned him not to depend too much on his own powers, but seek the aid of God. Then failing to make himself perfect, he had run to the other extreme and declared that there was nothing good in man at all, and that man could not of himself perform any worthy action. Finally he had hit upon the idea that justification means, "not an infusion of justice into the heart of the person justified, but a mere external imputation of it." Faith, in Luther's view, thus becomes an assurance that this imputation has taken place, and man accordingly need not give himself any more trouble about his salvation.