Even though Easter is not the beginning of the Roman Catholic liturgical year, it is the highpoint of the year. Easter is the celebration of the paschal mystery, coming from the word pascha, which means “Easter.”
There are a number of aspects of the paschal mystery incorporated into the celebration of Easter that makes it so embracive. One of these aspects, and perhaps the one that comes to the minds of most Christians when they think about Easter, is the memory of the life, death, and resurrection of Jesus.
Another aspect of the Easter mysteries is the presence of the risen Christ beyond the time of his human journey. The Resurrection—indeed the whole of the paschal mystery—is not a past event that we merely commemorate. It is part of our lives today, part of the life of the Church since the days of the community that was formed around Jesus of Nazareth, continuing and being built up in love as you stand in your assembly each Sunday at your own parish.
In the Gospels we do not find Sunday as a day for assembling the followers of Jesus, but we discover in all four Gospels that the Resurrection took place on a Sunday. (See Matthew 28:1-7, Mark 16:1-8, Luke 24:1-8, and John 20:1-18.) In addition to being the day on which Jesus had been raised from the dead, the first day of the week was also the day on which Jesus appeared to the disciples after the Resurrection....
We cannot, on the one hand, think of the Resurrection as merely an event in the life of the historical Jesus. That is wholly true, yet the Resurrection continues in the life of the Church. We experience the Resurrection when we celebrate the initiation of new members into our communities at the Easter Vigil. We experience the Resurrection when we celebrate the baptism of infants. We experience the Resurrection whenever we celebrate the sacraments. And we experience the Resurrection whenever we bond with those we love because they are gifts of God. Yet these experiences are only one side of the coin.
The Resurrection also was part of the experience of Jesus, the Son of God who shared his human life with us by his incarnation. And so the Resurrection also was part of the experience of the paschal mystery in the life of Jesus two millennia ago. That is the other side of the coin that is the Christian faith.
from An Introduction to the Church's Liturgical Year (an Our Catholic Tradition handbook) by Martin F. Connell