The length of three hundred cubits denotes this present age, which extends over three periods, namely, the period of natural law, the period of the written law, and the period of grace through which the Holy Church is from the world's beginning to its end advancing from this present life towards the future glory. The fifty cubits’ breadth denotes all believers everywhere, who are established under one Head; that is Christ. For fifty is seven times seven that is, forty-nine, the number that means the total sum of all believers—plus one, which means Christ, who is the Head of His Church and the goal of our desires. That is why the ark is gathered to one cubit at the top. The height of thirty cubits denotes the thirty volumes of the Holy Writ, namely, the twenty-two of the Old Testament and the eight of the New, wherein is contained the sum of all the things that God has either done, or else is going to do, for His Church. The three stories signify the three ranks of believers that there are in the Church, whereof the first have commerce with the world, albeit lawfully, the second are fleeing from it and forgetting it, and the third already have forgotten it, and they are near to God. The fact that the ark gets narrower towards the top and wider below means that in the Holy Church there are more people leading a carnal life than there are persons of a spiritual life, it being always the rule that the more perfect are proportionately few in number. The ark narrows to the measure of a single cubit at the top, because Christ, the head of his Church, who is the Saint of saints, is like to other men in all respects in nature, but in the uniqueness of His virtue He is above them all. The hundred years that the ark took to build means the same as a hundred cubits. For the hundred years signify the period of grace: since the Holy Church, which began with the beginning of the world, received redemption through the immolation of the spotless Lamb in the period of grace.