The Simple Answer
The simple answer is that the Resurrection occurred in the middle of the night. Of course, no one knew it had happened until Mary Magdalene and the other women disciples arrived at the tomb that Sunday morning and discovered that it was empty. But we know it happened! So why should we wait? At the very first moment of Pascha, at the very beginning of the day of the Resurrection, we begin the celebration!
Time Turned Upside Down
The simple answer is true enough. But it’s not the whole story. We know it’s not the whole story, and it can’t be the whole story, because, in the Orthodox Church, the day doesn’t start at midnight. As with the Jewish calendar, on our calendar, the day starts at sunset. The first service of any day is Vespers, which is the service held at or near sunset. So Pascha, and the celebration of the Resurrection, has to begin with Vespers.
But as the sun sets on Holy Saturday, the church is empty. A Vesperal Liturgy was celebrated on Saturday morning, or, in some parishes, in the early afternoon. That’s one of the liturgical characteristics of Holy Week – things get a bit weird. The days are turned upside down. We celebrate Vespers in the morning and Matins at night.
Chronos and Kairos
There’s a reason for that: In Greek, there were two kinds of time, chronos and kairos. Chronos is regular clock-and-calendar time. It’s time that is measured in minutes, hours, days and years. Kairos is different. It’s the time outside of time, the time in which God acts. In Holy Week, chronos and kairos seem to be at war with each other. We’re walking outside of time, remembering our Lord’s Passion, which occurred, not just in chronos time, but also before anything, even time itself, was created. It occurred in kairos time, and we join Him there.
And so the first Paschal liturgy is held early in the day on Holy Saturday. During the service, the cloths on the altar and on icon stands are changed from dark to white, and the priests change into white vestments. […] Holy Week is well and truly over. We see the light beginning to shine forth. But still we wait.
On that Sabbath when the Lord slept in the tomb, everyone alive thought that he was dead. We know he’s alive. And yet we wait with the women disciples. As they watched the sun go down, they didn’t know what we know. We know, but we wait with them, remembering the Sabbath when Christ’s body rested.
A Sunrise Service in the Middle of the Night
Shortly before midnight, we return to the Church for the midnight office. For a moment, chronos and kairos seem to match up. But time is still out of alignment. The moment the midnight office ends, Matins, the sunrise service, begins. So, in a sense, we do celebrate the Resurrection at sunrise. But it’s sunrise, kairos time. The sun no longer rules. Rather, it is the Son who shines forth from the tomb, granting light to the world! Christ is risen!