An Orthodox friend of mine invited me to attend the evening service on Good Friday. At the end of the service, the priest announced that “vigil will be kept at the Tomb of Christ throughout the night.” To what was he referring?
It is common in many parishes to hold such a vigil after the Matins service celebrated on the evening of Great, Holy and Good Friday. During this vigil, the faithful customarily read aloud from the Old Testament Book of Psalms until the beginning of the Vesperal Liturgy of Saint Basil on Great and Holy Saturday. [In most instances, everyone is free to volunteer to read, generally for periods of one hour.] After this Liturgy, in many parishes the vigil continues, with the faithful reading from the New Testament Acts of the Apostles until the beginning of the Paschal services, generally an hour or so before midnight on Saturday evening. Inasmuch as this Vesperal Liturgy speaks of the Resurrection of Christ, it constitutes, in a sense, the “first announcement” of this central reality, the cornerstone of our faith as Orthodox Christians. Hence, reading from the Acts of the Apostles, which speaks of the life of the early Church after Christ had been raised from the dead and the Holy Spirit descended upon the apostles on Pentecost, 50 days after Christ’s Resurrection, is most appropriate.
I might add that in the early Church, Holy Saturday was one of the main occasions on which those who had been preparing to be baptized—the “catechumens”—were received into the Church. It is said that some of the faithful would keep vigil with the catechumens during the hours leading up to their baptisms, offering them encouragement and final instructions while praying for and with them. While different in “form,” so to speak, the vigil also recalls this early Church practice. It is also customary among many Orthodox Christians to keep a vigil, during which the Psalms are chanted, over the body of someone who had recently reposed until the time of his or her funeral and interment. While I do not think that this custom is directly related to the vigil about which you enquire, it does recall for the faithful the importance of remaining vigilant for the coming of the Lord “in glory” throughout our early lives—something to which all Orthodox Christians aspire—and an affirmation of our belief in the universal resurrection of the departed.
For additional information on the services celebrated on the evening of Great, Holy and Good Friday and Holy Saturday, please see this link on our web site
Hope this helps!