The fasts, known as “Jejunia quatuor temporum,” or “the fast of the four seasons,” are rooted in Old Testament practices of fasting four times a year:
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. – Zacharias 8:19
“The observance of the Ember Days, a most venerable feature of the liturgical calendar, dates back to early Roman antiquity (they are older than Advent). Pope Leo I (c. 450) has left a series of beautiful sermons for these days. Originally the Ember Days were an occasion of thanksgiving for the three great harvests of wheat, grapes, and olives — all very meaningful symbols employed by the liturgy. In the Offertory procession the faithful brought tithes of the harvest to be used for the offerings then and there, for the support of the church, and for the poor.” “The Church’s Year of Grace” by Fr Pius Parsch
To a certain extent, the Ember Days resemble our own lives. In the springtime we receive supernatural life through Baptism (represented by the baptismal candle); throughout the summer and autumn of our lives our souls are nourished by the Body (the Host has been made from the kernels of wheat) and the Blood (the Chalice) of Our Lord. In the winter we reap the harvest of our good works as we begin our journey into eternity, fortified by Holy Viaticum and the sacrament of Extreme Unction (oil).
There was also a Jewish custom at the time of Jesus to fast every Tuesday and Thursday of the week. The first Christians amended both of these customs, fasting instead on every Wednesday and Friday: Wednesday because it is the day that Christ was betrayed, and Friday because it is the day that He was slain. The Roman appropriation of the Ember Days involved adding one day: Saturday. This was seen as the culmination of the Ember Week. A special Mass and procession to St. Peter’s in Rome was held, and the congregation was invited to “keep vigil with Peter.” Because Apostolic tradition prescribed that ordinations be preceded by fast and prayer (see Acts 13:3), Pope Gelasius I, used Ember Saturdays as the day to confer Holy Orders beginning in 494.
There is a different focus on each day of Ember Week:
Ember Wednesdays are dedicated to Mary; they are always “Mary’s Day”. All four ember Wednesdays were celebrated in the station church of St. Mary Major. Wednesday, devoted to our Lady, is a day of reflection and spiritual orientation.
Ember Fridays all take place in the stational church of the Basilica of the Apostles. As Fr Parsch puts it: “Ember Friday is the liturgy’s ‘Yom Kippur.’” Friday emphasizes conversion and penance.
Ember Saturdays all take place in the stational church of St. Peter. Saturday is a preview of Easter, and it marks the renewal of our baptismal covenant.
Ember Days were celebrated four times each year. They were tied to the changing of the seasons, but also to the liturgical cycles of the Church. Traditionally, the Ember Days were celebrated with fasting (no food between meals) and half-abstinence, meaning that meat was allowed at one meal per day. (If you’re observing the traditional Friday abstinence from meat, then you would observe complete abstinence on an Ember Friday.) In 1966, Pope Paul VI excluded the Ember Days as days of fast and abstinence for Roman Catholics.
Ember Weeks are the complete weeks following:
(1) Holy Cross Day (September 14);
(2) the Feast of St. Lucy (December 13);
(3) the first Sunday in Lent;
(4) Pentecost (Whitsunday).
Wednesday, Friday, and Saturday after Quadragesima Sunday (the first Sunday of Lent) are known as “Lenten Embertide,” which, depending on the date of Easter, can come as early as February 11, but which is seen as associated with the season of Spring (March, April, May).
Liturgically, the lessons for the Wednesday and Saturday Masses focus on the Commandments given to Moses by God, and on the promises to those who keep them well, all ending with the story of the three men saved by an angel from Nebuchadnezzar’ s furnace, as is so for all but Whit Embertide.
The Gospel readings speak of Our Lord discoursing on the sign of Jonas, and how exorcised spirits can return (Matthew 12:38-50), healing the paralytic (John 5:1-15), and the Transfiguration (Matthew 17:1-9).