Profound depression can alone account for the step he took in 1530, when, for a while, he discontinued his sermons at Wittenberg because he was sick of the indifference of his hearers to the Word of God and disgusted with their conduct. The editor of the sermons of this year, which have only recently been published, remarks justly, that “the only possible explanation of this step is a pathological one.”[539] Luther even went so far as to declare from the pulpit that he was “not going to be a swine-herd.”[540] Yet, a little after, during the journey to the Coburg, a sudden change occurred, and we find Luther making jokes and writing in a quite optimistic vein, and, no sooner had he reached his new abode, than he plunged into new literary labours. Nevertheless, whilst at the Castle, he was again a victim of intense depression, was visited by Satan’s “embassy” and even vouchsafed a glimpse of the enemy of God. On his departure from the Coburg good humour again got the better of him, as we see from his jovial letter to Baumgärtner of Oct. 4, 1530, and on reaching Wittenberg, he was soon up to his ears in work, so that he could write: “I am not only Luther, but Pomeranus, Vicar-General, Moses, Jethro and I know not who else besides.”[541] The facility with which his moods altered is again apparent when, in his last days, he left Wittenberg in disgust only to return again forthwith in the best of spirits. (See below, xxxix., 1.) Yet in his attitude to the olden Church this same man, who otherwise shows himself so instable, knows how to display such defiant obstinacy that Protestants who look too exclusively at this side of his character have even been able to speak of his inflexible firmness. What steels him here is his ardent belief in his calling.