Commentaria in Isaiam
They deny it, Cajetan and Abulensis, and Cajetan thinks they were only half-hours. “The reason is that if the ten degrees were hours, the shadow could not have advanced ten hours and also gone back ten hours, as Isaias proposes: for in either case, namely whether in the advance or in the going back of the shadow by ten hours, it would have been deep night, when there is no shadow.” On the contrary, that the sun went back ten hours St. Dionysius teaches, in his letter to Polycarp; the author of On the Wonders of Holy Scripture, book 2, chapter 27; the Chaldee, Bede, Angelomus and Eucherius on 4 Kings 20:7. The reason is that 10 degrees or lines on dials ordinarily signify whole hours. To Cajetan’s reason they reply that shadow is taken metonymically for the sun, as if to say: Wilt thou that the sun go forward ten hours, and deep night follow? or that it go back from the place where it now is, namely near sunset, to the place where it was in the morning ten hours before? But Cajetan’s opinion is more conformable to the words of Scripture, in which it says, 4 Kings 20: “Wilt thou that the shadow return?” and not the sun, and that on the dial; but this could not happen by night. The ten lines, therefore, are five hours, in which by day the shadow could both ascend and go back; and this is what Isaias says: “And the sun returned (namely by its shadow) ten lines by the degrees by which it was gone down”
Add that this descent through ten lines was given to Ezechias as a sign; therefore it could be noted and observed by him fully and in every part; but this could be done only on Cajetan’s view. Finally, Josue 10 says that at Josue’s command the sun stood still, “and one day was made as two, nor was there before or after so long a day.” But this will be false if this day of Ezechias was of 39 hours; for then this day would have been almost as long as three days. To the reason of St. Dionysius I reply that on the dial of Achaz, as also on some of ours, the hours were marked by halves, that is, in half-hours.
It is asked, thirdly, whether the going back of the sun was sudden, or successive by the ordinary motion of the sun? St. Dionysius in the place cited thinks the sun went back gradually, and spent ten hours in this going back, and as many hours again advanced to the same point, so that this day was increased to twenty hours, and was in all 32 hours. Others, and perhaps more probably, think the sun went back in a moment; or at least faster than usual, for example that it spent five hours in the going back; so that with the ten others, in which according to them it descended again, they make fifteen hours, by which this day was longer than others; so that as many hours were added to the day as years of life to Ezechias: “The reason is that, if the sun had been moved with its ordinary motion, Isaias would not fitly propose whether he wills the sun to go back or to advance ten hours, as if either were a miraculous sign; because in the ordinary advance of the sun there is no miracle, but only in a momentary or sudden one.” This day, therefore, according to them, was of 22 or 27 hours. Torniellus, moreover, in the year of the world 3392, number 6, thinks this day was longer than the others by ten hours. So many hours as years were added to Ezechias. This may be conjectured probably; for here nothing is certain.
You will say: Ezechias seems to recognize no miracle in the advance of the shadow; for he says: “It is an easy thing for the shadow to grow.”
I answer: Perhaps he did not fully grasp Isaias’s meaning. Secondly, I answer that “easy” means: it is easier for the shadow to grow, namely in a moment, than to go back in a moment: because the former is a miracle only as to the manner, the latter as to the manner and as to the thing. So Cajetan, Procopius and others.
It seems truer that Isaias, in a very brief time, raising his hand and as it were drawing it back, made that shadow return, so that the miracle might be visible and clear to Ezechias as he watched this sudden bringing back of the shadow: for “I will make to return” can refer both to Isaias and to the Lord. Add that only at midday could the shadow either ascend or descend ten degrees, that is, five hours.
From these considerations likewise, namely first, that there was an ascent and descent of the shadow; secondly, that at the least ten hours were marked; add thirdly, that the shadow grew by ascending; it seems to be gathered that this dial was a vertical southern one, or certainly a concave hemispheric one likewise southern, erected to the elevation of the pole; in which two alone those three things can conveniently be saved; and it is more probable that it was vertical, first, because this is more conspicuous and better suited to the common use of the palace of king Ezechias; secondly, because it is rarer to find an open and raised place, such as that hemispheric one requires, in which the hours from sunrise to sunset are designated; but the vertical is most conveniently drawn on any wall whatever; thirdly, because there is not so properly an ascent, nor so properly an increase of the shadow in a concave as in a vertical one; fourthly, because Procopius makes the steps of the house of Ezechias’s father those steps of the dial, which suits a vertical, not a concave one: for there is no ordinary part of a house fit for describing concave dials.
Hence note: Isaias does not say: “Wilt thou that the shadow ascend, or return?” For it was midday; therefore the shadow was at its lowest descent, so that from midday it must ascend again until evening, as in going back likewise to the morning it would have had to ascend. Whence Ezechias says: “It is an easy thing for the shadow to grow” (to ascend, therefore, is to advance, and so to grow is opposed to going back and returning), because naturally, ascending from midday, it grows always until evening, when it is greatest and longest. As, therefore, in the morning the shadow is greatest, and gradually decreases until at midday it is least; so again from midday it gradually grows toward sunset, when it is as great as in the morning.
Ask fourthly, what hour of the day it was when this miracle began, and so where the sun was when it began to go back? I answer: It seems to have been midday, when the sun went back: for hitherto the shadow had descended, as is plain from verse 8; in future, however, an ascent remained, as is plain there; therefore the shadow was at the midpoint of ascent and descent at the time when Isaias offered the miracle to Ezechias: and no point of the day seems able to bring this diversity of the shadow except midday, especially on a dial denoting at least ten hours, such as that of Achaz was on every view; and in a place at about the 33rd degree of pole elevation, as Palestine is (where the shortest day is a little less than 10 hours, the longest a little more than 14); therefore, and so on. There is an elegant riddle about the shadow, of Theodectes, in Hermippus, in the book On the Disciples of Isocrates: “There is,” he says, “a certain thing which is greatest about its rising and its end, but least about its standing and vigor.” Surely this shadow is the symbol of our life, soon vanishing. Wherefore God willed that in the shadow of the human body, nay of the nose and the fingers, there should be a constant and natural horologe, which should always warn man of ever-flowing life and time. To say nothing else, this saying is known:
If your nose be set toward the sun, with your mouth open, you will learn by your teeth what hour it is.
It is asked, fifthly, whether the sun alone went back? Abulensis answers, and St. Dionysius indicates, that all the heavenly spheres went back with the sun alone, just as when the sun stood still under Josue the moon also stood, as is said in Josue 10:12; and consequently all the heavenly spheres stood still. The reason is that otherwise the whole order and harmony of the heavens would have been disturbed, and a greater miracle would have been needed.
Note these three miracles, namely first, the sun’s standing still under Josue; secondly, the sun’s going back under Ezechias; thirdly, the sun’s being eclipsed at full moon when it is opposite the moon, as happened at the passion of Christ; these three, I say, happened in the very heavens and stars: but the star that led the Magi to the crib of Christ, and the fire descending from heaven at the prayers of Elias, happened not in the starry heaven but in the aerial, that is, in the air itself.