108 The seventh trumpet, then, seems to signify the sabbath of the week, which is reckoned not only in days and years and periods (for which reason the number of the jubilee is sacred), but includes also the seventieth year, when the people returned to Jerusalem, who had remained seventy years in captivity. In hundreds also and in thousands the observation of the sacred number is by no means passed over, for not without a meaning did the Lord say: “I have left the seven thousand men, who have not bent their knees before Baal.” Therefore the shadow of the future rest is figured in time in the days, months, and years of this world, and therefore the children of Israel are commanded by Moses, that in the seventh month, on the first day of the month, a rest should be established for all at the “memorial of the trumpets;” and that no servile work should be done, but a sacrifice be offered to God, because that at the end of the week, as it were the sabbath of the world, spiritual and not bodily work is required of us. For that which is bodily is servile, for the body serves the soul, but innocence makes free, guilt reduces to slavery.
Source: On the Death of Satyrus (New Advent)