Today the Church celebrates Quinquagesima (Fifty Days) Sunday, traditionally called “Carnival Sunday” because the Lenten fast for the priests began tomorrow and it was the last day the priests could eat meat (excepting Sundays) until Easter. Quinquagesima Sunday is the third and final Sunday of the season of Septuagesima (Seventy Days), which the Church has kept for more than 1,000 years as a kind of preparation for the solemn fast of Quadregesima (the Forty Days of Lent).
Septuagesima is a vitally important liturgical season because it places before our minds and hearts our depraved sinfulness whereby we have mortally wounded ourselves. In that way, it is a kind of extended meditation on our need for a Savior and on our need for Lent. The Church assists us in this meditation in various ways. As Israel was seventy years in captivity in Babylon, the Church keeps the Seventy Days (63 days is rounded to 70) of preparation for the return to Jerusalem that is Easter. While we are in Babylon, however, we cannot sing the song of the Lord on alien soil, and so we abstain from the Alleluia from Septuagesima Sunday until Easter. This places before our minds the bleak reality of our exile. By our sins, we have left our homeland. During Septuagesima, we keep focused on getting back home.