Abulensis’s answer (q. 4) is ready and easy: this number was definitely employed because it so pleased God. “For what has pleased the prince has the force of law” [Digest, On the constitutions of princes, law “Quod principi”]. And, as readily and easily as this is said, so too that it is true cannot be denied. But that cause [is], in all things, a general [one]…
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…[But that cause, in all things, is a general one]; and, though the mind is not ignorant of it — especially [a mind] steeped in true piety — yet it advances, and still inquires whether some fitting reason can be adduced, why the Lord should seem to have willed it. Others, therefore, answer that the number seven is sacred, and pleasing to God in many things. “See,” says St. Bernard (sermon 15 on the Canticle, near the end), “seven is a sacred number; it is not idle.” St. Jerome, on Galatians ch. 5: “To the faith,” he says, “is given the seventh, and more sacred, place.” And again: “the seventh place,” he says, “the striving holds — [seven being] as it were a consecrated and eminent number among the vices.” [St.] Bede, on Acts ch. 6, says the deacons were seven “not without the mystery of the sevenfold number.” Similar [things say] St. Nazianzen, oration 44 on Pentecost, and the oration on the Maccabees; St. Augustine, in the book On the Spirit and the Soul, ch. 62, [and] book 11 of the City [of God], ch. 31; Philo, On the Contemplative Life; and, among the profane [authors], Cicero, in the [Dream of Scipio], when he calls [seven] “the knot of all things”; the most ancient of the Greek poets, Linus, “the origin of all things”; Censorinus, in the book On the Birthday, ch. 5: “The seventh number,” he says, “among the Jews is [foremost] in the reckoning of all times.” For [Scripture] regards the seven days of the week, the seven weeks of Pentecost, the seven years of the land’s sabbath, the seven weeks of years of the Jubilee. Tacitus (book 5 of the Histories): “Most of the heavenly [bodies] accomplish their force and course by sevenfold numbers.” See Nicomachus of Gerasa in [his] Arithmetic; Rhodiginus, book 4, ch. 24, [and] book 22, ch. 12; Cassanaeus, On the Glory of the World; Gerard Vossius on the Dream of Scipio; our own Salmerón, in the prologue to the Gospels, 20; and several others, whom I have cited [in my commentary] on Tobit, ch. 12, q. 7. And by these [authorities] enough is indeed done for the proposed question; yet the human mind does not yet rest — it presses, insists, ponders: why, and whence, [comes] to this number so great a sanctity, or grace, and authority? Masius, on this very passage (fol. 107 and following), with great and diligent zeal and effort, strove to settle this question. For he says that there are seven kinds of all things, of which this whole universe consists, and outside which nothing at all anywhere either is, or can be; and therefore the sevenfold [number] deservedly, among all [peoples], has so [great] a name, mystery, and veneration. The first kind of things is spiritual creation — namely, the Angels themselves. The second, simple bodies — the heavens and the elements. The third, mixed inanimate bodies. The fourth, mixed bodies animated with that soul only which gives life alone — as trees, plants. The fifth, [bodies] animated with that soul which, together with life, bestows sense — as are the brutes. The sixth, [bodies] animated with a soul which, together with life and sense, furnishes intellect — as [is] man. The seventh — which can also be called the first — is God, the author and creator of all these: the beginning and end of all, from whom all things began, and into whom all things end. Hence, therefore, in the very creation of things [there is] a week of days, whose six former days correspond to the six kinds of created things; but the Sabbath [corresponds] to the seventh kind of things, [being] dedicated and consecrated to God the Creator — so much so that the Cabalists say that “whoever does not keep the Sabbath thinks rightly neither about the creation of the world nor about the future life.” Hence thereafter, in sacred [rites], and in the rites and institutions of various [kinds], the sevenfold [number] was employed, and the number held in esteem, for the perpetual memory and signification of so great a mystery. All [this is] fitting enough. Yet someone could still inquire, why the kinds of ani- mate [things] are here divided more minutely than [the kinds] of other things? why those six kinds of creatures were not created distinctly on six days, each on its own? For — to say nothing of other [difficulties] — when the Angels were created is still undecided [sub iudice]. Finally, why were not more or fewer kinds of things created? Namely, in that kind [of question] we cannot cut everything to the quick by the reasons of the divine counsel and will. Yet a reply can be made to all these [questions]. But because the reply would have to be fetched from the various, multiform opinions which are [held] in the debates of Philosophers and Theologians, the Reader will be content with the things hitherto adduced; but [I add this], so that I may indicate some proper causes of this question. And these will be twofold. For, first, because the sevenfold number not rarely signifies not a definite [number], but the more frequent repetition of some thing — as will be said [at] Kings, ch. 2 — we can here generally reckon that there were seven priests for this reason: that there might be signified all that multitude of them, whether of Angels or of men, who, from duty, from charity, and by the inspiration or command of God, use — with their prayers before Him, and with their voices and admonitions before their neighbor, as certain trumpets — [these instruments], so that the vanity and perversity of this world may be overthrown in the minds of all, [and] that the walls and all the impediments, by which the approach to their hearts is blocked against the feet of the holy Israelites who evangelize peace, may be cut down. For to each of these it is said, “Cry, cease not, lift up your voice like a trumpet, and announce to my people their crimes” (Isa. 58:1, and ch. 40:9). Trumpeters of this kind were the Prophets, the Apostles, and all Apostolic men — so that, in the life of St. Bernard, it is written that, against the schism of Peter Leonis [Anacletus II], “as [one summoned] to demolish Jericho, the priestly trumpeter was called out” (book 2, ch. 7), and elsewhere. Thus, by the seven trumpets of them, we understand all [those things] which they use as instruments toward the aforesaid end — whether they be supernatural or natural — such as eloquence, erudition, [and] the charisms of the Holy Spirit. Through all these, the voice of them, most clear for moving the minds of men — whose hearts, ensnared by the pleasures of this world, are touched by no care or thought of heavenly things — is wont, in breaking through [those hearts], to be poured forth quite wonderfully. All these [things], if they be regarded in themselves, are small, and of no great moment, and cheap — like rams’ horns; yet when they are handled at God’s nod, and serve his will and praise, they are the trumpets of the Jubilee: they arouse true peace, true liberty, and true jubilation and joy — [and] to them no power of the world, no obstacles of impious men, no engines of the hellish enemies can resist. By the seven days — of all the ages, in which the Jericho-like beauty and pleasantness of this world seems to flourish and endure — we understand the whole span. For this consists of the constant weeks of rolling and re-rolling days; and though it seem very long, it is very short, [being only] like seven days. By the seven circuits on the seventh day — are there not denoted the pilgrimages, the courses, and all the labors of all the pious and true Israelites, by which they are wearied in this world? Jericho standing and flourishing they never en- …
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…[Jericho standing and flourishing they never] enter, but only go around — that is, they never give themselves wholly to the pleasures and empty joys of this world; but, sober, chaste, and holy, they walk around them only, seeing them, yet despising them, and desiring [them] overthrown.
Secondly, specifically: the sevenfold number of priests not unfitly designates those seven Princes of the Angels, of whom I have said much [on] Tobit 12. Nay, it can also signify the seven lower orders of Angels; to which, if there be joined — as Cherubim and Seraphim — the two others [priests], who carried the ark on their shoulders, we shall see all the choirs of Angels, with their various offices, venerate, worship, and proclaim the humanity of CHRIST the Lord; be present to the multitude of pious Israelites; with their jubilating trumpets, arouse it to all piety, religion, and the hatred and storming of the vices, and console and refresh it; but to the wicked metropolis of the worldly, announce and threaten ruin and destruction, and at last — while they [the worldly] do not repent — inflict [it], just as [do] the seven Angels, with the seven trumpets, in the Apocalypse. There are signified also the seven orders of the Church, to which those carrying the ark come up — [namely] the Episcopate, and the Supreme Pontificate. There are signified men marked with the seven gifts of the Holy Spirit: the seven heralds of the sacraments, and the trumpeters against the heretical Jericho of our time — the stormers of the seven capital vices, as of the strongest walls.
The seven trumpets are those very [things] which I have already called the seven gifts of the Holy Spirit, the seven sacraments, and also the seven liberal arts — by whose force, and right and holy use, as I said before, the Jericho-walls of the vices, of infidelity, and of all heresies can be shaken, cast down to the foundations, and prostrated.
The seven days are [the days] of this world, of which I have spoken in Genesis: six ages, together with the eternity adjoined — which the Apostle teaches (Heb. ch. 4) is signified by the seventh day, or Sabbath. There are also the seven days of the week, on which the pious constantly worship God — whence, the Gentile [names] having been rejected (of the Sun, Moon, Mars, and other like names), they are better called feriæ by the Church. What too [of] the seven grades of age in men — infancy, boyhood, adolescence, youth, settled age, old age, and decrepit senility? But let the opinion of Rupert too be heard (ch. 9): “Why,” he says, “must one go around the city six days once per day, but on the seventh day seven times? Namely, because the city of the devil is to be judged both for the creature of the world — whence it could have known the Creator — and for the coming of the Son of God, whom it does not receive. The circuit of six days signifies the judgment of the sixfold creature [creation]. For in six days all these [things] were created. And the Apostle, when he had said that ‘what is known of God is manifest in them, for God manifests [it] to them,’ immediately subjoined: ‘For his invisible [attributes], from the creation of the world, are clearly seen, being understood through the things that are made — his eternal power also and divinity — so that they are inexcusable, because, when they had known God, they did not glorify [him] as God, nor gave thanks,’ etc. [Rom. 1:19–21]. Therefore, for six days, once on each single day, the enemy city is encircled, because through the understood creature of the world the impiety of men — who did not approve of holding God in [their] knowledge — is to be judged. But sevenfold — that is, most greatly — [they are to be judged], and [they are] to be judged more in every way through the coming of the Son of God, because they did not receive him. For did they not indeed hear? ‘And indeed, into all the earth their sound went out,’ etc. [Rom. 10:18]. They heard, the heavens narrating; and they saw ‘his tabernacle set in the sun, nor is there any that hides himself from his heat’ [Ps. 18:6–7]. This [is] said as marvelously as truly — [namely], that the coming of the Son of God was no more hidden from them than that sun which is seen by all. For this [reason], I say, they are to be judged more, and by this they will be most greatly inexcusable. Therefore this too was rightly said or done, that — with each of the other days once — on the seventh day the city should be circled seven times. For the seventh [is] the day on which God rested from all work. The seven circuits on the seventh day are the seven actions by which the blessed in heaven clearly see God, sincerely love [him], constantly praise [him], clearly enjoy [him], are delighted without any interruption, bless their own bodies, and all exult among themselves in a most joyful fellowship — and that unto all eternity thereafter, as the circuits made around [the city] suggest. For what would you call first, what last, in a circle? But also in this [present] life, the same seven circuits admonish [us] to use well the seven gifts of the Holy Spirit, well the seven sacraments of the Church, well the seven liberal disciplines, well our seven ages, well the seven days of the week: and with these to fight against Jericho, and to storm all its gates, ramparts, and walls.” It also seems to me to be signified that, with a more earnest care, the holy Angels — [beings] loving our salvation — admonish and urge us when the last time of life is at hand. For what at other times they do as it were once, this they then do sevenfold; just as, on the contrary, the demons then too solicit us to [our] fall much more vehemently, cunningly, and frequently. It is given, finally, to understand what fervor of piety, at that same extreme term of our life, and what care and assiduity in the service of God — what diligence, solicitude, and effort — ought to be [expended] in the hearing of the divine trumpets, in the escort of the ark of the covenant, and in the plucking-out and casting-down of the walls of Jericho, that is, of all the vices.