(4) Why does God command the ark to be smeared with pitch, both on the inside and on the outside? (#Ge 6:14). Pitch is so called by reason of its bird-lime like tenacity, because it glues together whatever was disunited before, so as to form one indissoluble and indivisible joint. For everything which is held together by bird-lime is immediately held to a natural union; but our body being composed of many parts is united on the outside, and is held together by its own proper habit, but the previous habit of connection which binds those things together is the soul, which, being situated in the middle, penetrates through every part till it reaches the surface, and then is turned back again from the surface to the centre, so that our spiritual nature is rolled up compactly in a double fold, being united in a firm solidity and union. Therefore this ark is smeared with pitch, both on the inside and the outside, for the reason here given. But that ark which is placed in the holy of holies, and as covered over with gold, is the similitude of the world appreciable only by the intellect, as is declared in the account given of it: since just as there is a world appreciable by the intellect incarnate in incorporeal figures existing at the same time, consisting of a union of all figures by a certain invisible harmony; for, in proportion as gold is a more noble material than pitch, in the same ratio is that ark, which is in the holy of holies, superior to this one of which we are now speaking. And again, God ordained that its measure should be quadrangular, from a regard to usefulness; but his object in the other ark was not so much that it should be useful as that it should be exempt from all possibility of decay; for the nature of incorporeal things, appreciable only by the intellect, is to be exempt from decay, being incorruptible and permanent. The one ark is tossed to and fro by the winds and the waters, but the other has its station constantly in the holy of holies; and being stable it is akin to divine nature, as the other, which is tossed about in every direction, and moved from one place to another, is akin to and the emblem of created nature. Besides this, that ark of the flood being, as it were, an example of corruption, is raised on high, but the other, which is in the holy of holies, imitates the incorruptible condition of eternity.