On the profoundest questions of moral teaching, it is, according to Luther, the “inward judgment” that is to decide what “spirit” must be followed. “For every Christian,” he writes, “is enlightened in heart and conscience by the Holy Ghost and by God’s Grace in such a way as to be able to judge and decide with the utmost certainty on all doctrines.” It is to this that the Apostle refers when he says: “A spiritual man judges all things” (1 Cor. iii. 15). Beyond this, moreover, Scripture constitutes an “outward judgment” whereby the Spirit is able to convince men, it being a “ghostly light, much brighter than the sun.”[248] It is highly important “to be certain” of the meaning of the Bible,[249] though here Luther’s own interpretation was, needless to say, to hold the field. The preachers instructed by him were to say: “I know that the doctrine is right in God’s sight” and “boast” of the inward certainty they shared with him.[250] Luther’s rules for the guidance of conscience in other matters were quite similar. Subjectivism becomes a regular system for the guidance of conscience. In this sense it was to the person that the final decision was left. But whether this isolation of man from man, this snatching of the individual from dutiful submission to an authority holding God’s place, was really a gain to the individual, to religion and to society, or not rather the reverse, is only to be settled in the light of the history of private judgment which was the outcome of Luther’s new principle. Of himself Luther repeats again and again, that his knowledge and conscience alone sufficed to prove the truth of his position;[251] that he had won this assurance at the cost of his struggles with conscience and the devil. Ulenberg, the old writer, speaking of these utterances in his “Life of Luther,”[252] says that his hero mastered his conscience when at the Wartburg, and, from that time, believed more firmly than ever that he had gained this assurance by a Divine revelation (“_cœlesti quadam revelatione_”), for which reason he had then written to his Elector that he had received his lead solely from heaven.[253] In matters of conscience wherever the troublesome “Law” comes in we can always trace the devil’s influence; we “must come to grips with him and fight him,”[254] only the man who has been through the mill, as he himself had, could boast of having any certainty: “The devil is a juggler. Unless God helps us, our work and counsel is of no account; whether we turn right or left he remains the Prince of this world. Let him who does not know this just try. I have had some experience of this. But let no one believe me until he too has experienced it.”[255]