sentences:  However, the all-night vigil is usually abridged so as to not last literally "all-night" and may be as short as two hours; on the other hand, on Athos and in the very traditional monastic institutions, that service followed by the hours and Liturgy may last as long as 18 hours.When the feast is a weekday (or, in the Russian tradition, on any day for Christmas, Theophany), Vespers (with the Liturgy in most instances) is served earlier in the day and so Great Compline functions much as Great vespers does on the vigils of other feast days.The Divine Liturgy is the Sunday sabbath worship service of the Orthodox Church.