Francis was struck with this advice, and although on other occasions he was in the habit of saying with Isaiah, "My secret is to myself," he communicated to them all what had passed in the apparition, but always with great fear; adding, that He who had appeared to him, had communicated things to him which, while he lived, he never would disclose to any one. We must believe, as St. Bonaventure remarks, that the seraph whom he saw attached to the cross in so wonderful a manner, or rather, Jesus Christ Himself in the appearance of a seraph, had said to him, as he had to St. Paul, "Secret words, which it is not granted to man to utter;" either because there are no words in which they can be expressed, or, as a respected author thinks, because there are no souls sufficiently disengaged from sensible objects, and sufficiently pure, to understand them. The confidence which Francis had reposed in his companions, did not prevent his taking every precaution possible to hide, as much as it was in his power, the sacred marks with which the King of kings had secretly favored him. From that time forward, he kept his hands covered, so that the nails should not be seen, and he wore slippers, which covered those of his feet. Wading saw in the Monastery of the Poor Clares at Assisi, the sort of slippers which St. Clare made for her spiritual Father, so neatly contrived that the upper part covered the heads of the nails, and, the underneath being somewhat raised, the points did not prevent his walking; for these miraculous nails did not take from him the use of his hands and feet, although it was painful to him to use them.