Those of us who treat Jesus' resurrection as simply an historical event that put God's seal of approval on his ministry and teachings probably don't understand the significance of today's celebration.
It's easy to confuse resurrection with resuscitation. In the latter, we presume someone dies, and then comes back to life. But the resuscitated individual is still basically the same person he or she was before they died. For instance, when Jesus tells Mr. and Mrs. Jarius to give their twelve year old resuscitated daughter something to eat in Mark 5, we take for granted that if the girl liked pepperoni pizzas before she died, they'd pop a pepperoni pizza in the oven for her now that she was alive again.
Resurrection is quite different. Technically Jesus is the only gospel person who rises from the dead. Jarius' daughter, the widow of Nain's son, and Lazarus were all resuscitated. As Paul put it, when one rises one becomes a "new creation." He once reminded the Christian community in Galatia that, unlike the historical Jesus, the risen Jesus isn't Jew or Gentile, slave or free, man or woman. The risen Jesus is a completely unique person, and our experiences of him/her are just as unique.
Perhaps that's why, in today's Acts passage, Luke has Peter tell the about-to-be-baptized Cornelius, "This man God raised on the third day and granted that he be visible, not to all the people, but to us, the witnesses chosen by God in advance, who ate and drank with him after he rose from the dead." Somehow Peter and his friends have had an experience of the risen Jesus - an experience that those who don't believe in him have never had. Only after they've encountered this new creation can they preach the good news of his/her presence to others.
I presume if I, like Jesus, had been unjustly executed, and after three days had risen from the dead, that the first persons to whom I would appear would be the people who had engineered my death. Pilate, Judas and Caiaphas would be high on my list. Yet those names obviously weren't on the risen Jesus' list.
In order to experience him/her alive in our midst, we have to have faith that he/she is in our midst. Those who killed him lacked that faith - just as some of us have yet to acquire it.
The author of John's gospel presumes such faith isn't necessarily an instant phenomenon. It takes longer for some than for others. In today's pericope, for instance, Mary of Magdala, after discovering the tomb is empty, simply believes it's a sign someone has stolen Jesus' body. Peter and the Beloved Disciple, on the other hand, seem immediately to conclude that the lack of a body means he's risen from the dead. One experience doesn't fit all.
Yet, the Pauline disciple responsible for Colossians makes a statement about the resurrection with which all early Christians would agree: "If you were raised with Christ, seek what is above .... For you have died, and your life is hidden with Christ in God." Only those who die with Christ experience Christ alive.
The risen Jesus doesn't just unexpectedly walk into our living room one day and announce, "Here I am!" As Christians we presume he/she's always here among us, working effectively in our daily lives. But Christ's presence only becomes evident, when we die as he died: when we give ourselves for and to others.
On this day of all days, we should not only be commemorating what happened to Jesus on Easter Sunday morning. We should also be commemorating what happens to us when we join him in becoming other Christs, far beyond just Easter Sunday morning.