The Liturgical Week
Every day in the week has its own liturgical theme, some of them tied to the life of Christ. Thus, Sunday focuses upon the theme of Christ’s Resurrection, while Friday focuses upon the theme of his Cross. Saturday, the Sabbath, recalls the time when Christ rested in the tomb, and so the theme for that day focuses upon the departed who rest in the tombs. The days and their respective themes are:
Sunday
the Resurrection of Christ
Monday
the angels
Tuesday
St. John the Forerunner
Wednesday
the passion of Christ / His betrayal; also, the Theotokos
Thursday
the apostles and St. Nicholas
Friday
the Cross
Saturday
the departed and the martyrs
As in Judaism, the liturgical day begins with the previous evening, so that (for example) Saturday evening Vespers focuses upon the resurrection of Christ, as do the services on Sunday morning. Sunday evening, however, belongs liturgically to Monday, and so focuses upon the angels, as do the services on Monday morning. (Fasting, one notes, is ascetical, not liturgical, and is counted from midnight to midnight.)
These themes are reflected in the liturgical hymns written for the days of the week, especially for the services of Vespers and Matins found in the Octoechos, the book containing the hymns for the eight tones.
Read more: Holy Week (opens in a new tab), Church Order and Liturgy (opens in a new tab)