Nativity Fast

The corresponding Western season of preparation for Christmas, which also has been called the Nativity Fast[2] and St. Martin's Lent, has taken the name of Advent.

The Eastern fast runs for 40 days instead of four (in the Roman Rite) or six weeks (Ambrosian Rite) and thematically focuses on proclamation and glorification of the Incarnation of God, whereas the Western Advent focuses on three comings (or advents) of Jesus Christ: his birth, reception of his grace by the faithful, and his Second Coming or Parousia.

Each individual is expected to confer with their confessor regarding any exemptions from the fasting rules, but should never place themselves in physical danger.

'preparation'), on which no solid food should be eaten until Sirius is seen in the evening sky (or at the very least, until after the Vesperal Divine Liturgy that day).

If Paramony falls on a Saturday or Sunday, the day is not observed as a strict fast, but a meal with wine and oil is allowed after the Divine Liturgy, which would be celebrated in the morning.

Many churches and monasteries in the Russian tradition will perform the Lenten services on at least the first day of the Nativity Fast.

These last are significant not only because of their perseverance in fasting, but also because their preservation unharmed in the midst of the fiery furnace is interpreted as being symbolic of the Incarnation—the Virgin Mary conceived God the Word in her womb without being consumed by the fire of the Godhead.

In the Russian usage, the hangings in the church are changed to the festive color (usually white) at the beginning of the Forefeast.

There are also special Epistle (Colossians 3:4–11) and Gospel (Luke 14:16–24) readings appointed for the Divine Liturgy on this day.

Some of the hymns are similar to those of Theophany (Epiphany) and Great and Holy Friday, thus tying the symbolism of Christ's Nativity to his death on the Cross.

During the Vespers, eight Old Testament lections ("parables") which prefigure or prophesy the Incarnation of Christ are read, and special antiphons are chanted.

If the Feast of the Nativity falls on a Sunday or Monday, the Royal Hours are chanted on the previous Friday, and on the Paramony the Vesperal Divine Liturgy of St. John Chrysostom is celebrated in the morning, with its readings and antiphons, and the fasting is lessened to some degree—a meal with wine and oil being served after the Liturgy.

In the Coptic Orthodox Church, an additional fast is observed on the three days before the beginning of the Nativity Fast, to commemorate the miraculous moving of the mountain of Mukattam (which lies within a suburb of Cairo) at the hands of Saint Simon the Tanner in the year 975, during the rule of the Muslim Fatimid Caliph Al-Muizz Li-Deenillah.

In modern times within the Byzantine Rite Catholic Church, the fast is largely kept on a voluntary basis with the faithful allowed to determine on their own the degree to which they wish to adhere to the traditional rules.