21. What man, again, knows how the angels made or took those clouds and fires in order to signify the message they were bearing, even if we supposed that the Lord or the Holy Spirit was manifested in those corporeal forms? Just as infants do not know of that which is placed upon the altar and consumed after the performance of the holy celebration, whence or in what manner it is made, or whence it is taken for religious use. And if they were never to learn from their own experience or that of others, and never to see that species of thing except during the celebration of the sacrament, when it is being offered and given; and if it were told them by the most weighty authority whose body and blood it is; they will believe nothing else, except that the Lord absolutely appeared in this form to the eyes of mortals, and that that liquid actually flowed from the piercing of a side which resembled this. But it is certainly a useful caution to myself, that I should remember what my own powers are, and admonish my brethren that they also remember what theirs are, lest human infirmity pass on beyond what is safe. For how the angels do these things, or rather, how God does these things by His angels, and how far He wills them to be done even by the bad angels, whether by permitting, or commanding, or compelling, from the hidden seat of His own supreme power; this I can neither penetrate by the sight of the eyes, nor make clear by assurance of reason, nor be carried on to comprehend it by reach of intellect, so as to speak thereupon to all questions that may be asked respecting these matters, as certainly as if I were an angel, or a prophet, or an apostle. “For the thoughts of mortal men are miserable, and our devices are but uncertain. For the corruptible body presseth down the soul, and the earthly tabernacle weigheth down the mind, that museth upon many things. And hardly do we guess aright at things that are upon earth, and with labor do we find the things that are before us; but the things that are in heaven, who hath searched out?” But because it goes on to say, “And Thy counsel who hath known, except Thou give wisdom, and send Thy Holy Spirit from above;” therefore we refrain indeed from searching out the things which are in heaven, under which kind are contained both angelical bodies according to their proper dignity, and any corporeal action of those bodies; yet, according to the Spirit of God sent to us from above, and to His grace imparted to our minds, I dare to say confidently, that neither God the Father, nor His Word, nor His Spirit, which is the one God, is in any way changeable in regard to that which He is, and whereby He is that which He is; and much less is in this regard visible. Since there are no doubt some things changeable, yet not visible, as are our thoughts, and memories, and wills, and the whole incorporeal creature; but there is nothing that is visible that is not also changeable.