When he opened the fifth seal, I saw under the altar the souls of those who had been slain for the word of God and for the witness they had borne. They cried out with a loud voice, “O Sovereign Lord, holy and true, how long before you will judge and avenge our blood on those who dwell on the earth?” Then they were each given a white robe and told to rest a little longer, until the number of their fellow servants and their brothers should be complete, who were to be killed as they themselves had been. (Revelation 6:9-11)
Reading the Apocalypse today I was reminded that souls in heaven are not only very much aware of what goes on here, but they expectantly wait for the Day of Judgment and the ushering of the New Heavens and New Earth.
Revelation was written 60 years after the Church was already conducting liturgies. In fact, all of the New Testament was written decades after the Church was conducting liturgies. The Divine Liturgy is based on Scripture, but much of Scripture is based on the Divine Liturgy.
Scripture is not a book that fell from heaven, when Christ ascended, already written, so that people would build Christianity based on a right interpretation of it. That’s confusing it with another book – the Qur’an. Rather, Scripture was an expression of the tradition of the Apostles and their successors, conceived in the womb of the Church, based on the teachings of the Church, protected and canonized by the Church, and propagated by the Church to the ends of the earth.
In this case (among many others), Revelation uses the imagery of something the Church had practiced from the beginning: worship sites by the relics of the martyrs. Their relics, from the beginning were considered holy and the most special places of prayer and worship on earth (an old tradition even in Judaism, e.g., 2 Kings 13:21). To this day, the Church only builds altars on top of relics of saints; in every parish, all over the world.