(20) What is the meaning of the expression, “And the water was greatly increased, and bore up the ark which floated upon the water?” (#Ge 7:17). The literal meaning is plain enough, but it contains an allegorical reference to our bodies, which ought to be borne up as if on the water, and by fluctuating with our necessities to subdue hunger and thirst, cold and heat, by which it is agitated, disturbed, and kept in motion.
(21) Why did the water overflow fifteen cubits above all the highest mountains? (#Ge 7:19). With respect to the literal statement we must remark that the excess was not merely one of fifteen cubits above all high mountains but above those which were a great deal more lofty and high than some others; therefore it was a great deal more than that height above the lower ones. But we must interpret this statement allegorically; for the loftier mountains shadow forth the senses in our body, because it has been permitted to them to occupy the abode of stability in the lofty region of our head. And there are five numbers of these, each to be considered separately, so that they amount in all to fifteen.