Zacharias 8:19 records the tradition of fasting four times a year to focus on God through His creation:
Thus saith the Lord of hosts: The fast of the fourth month, and the fast of the fifth, and the fast of the seventh, and the fast of the tenth shall be to the house of Juda, joy, and gladness, and great solemnities: only love ye truth and peace.
The Catholic seasonal fasts are called Ember days (the word comes from the old Anglo-Saxon ymbren, a circuit or revolution), and they coincide roughly with the change of the seasons: the week between the third and fourth Sundays of Advent (Winter), between the first and second Sundays of Lent (Spring), between Pentecost and Trinity Sunday (Summer), and the week beginning on the Sunday after Exaltation of the Holy Cross (September 14 — Autumn). The days were inconsistent until Pope Innocent II fixed them at the Council of Clermont in 1095.
The fasts are observed on the Wednesday, Friday, and Saturday of each Ember week.
This week is referred to as “Michaelmas” Embertide because of its proximity to the Feast of St Michael, the 29th of September.
The Autumnal Equinox is tomorrow, and hastens the shortening of days. The Church Year, which revolves around the birth and sacrifice of Our Lord, coincides at least roughly with this lengthening and shortening of days: We celebrate the birth of Our Lord on December 25, and as He was light in our world, the days grow longer. As the Church Year comes to a close, the days grow shorter, and darkness prevails.
As our days grow shorter, and harvest-time becomes more challenging, let us remember the prophecy of Amos 9:13-15:
Behold the days come, saith the Lord, when the ploughman shall overtake the reaper, and the treader of grapes him that soweth seed: and the mountains shall drop sweetness, and every hill shall be tilled.
And I will bring back the captivity of my people Israel: and they shall build the abandoned cities, and inhabit them: and they shall plant vineyards, and drink the wine of them: and shall make gardens, and eat the fruits of them. And I will plant them upon their own land: and I will no more pluck them out of their land which I have given them, saith the Lord thy God.