God raised Jesus from the dead on the third day and granted that he be visible, not to all people, but to us, the witnesses chosen by God in advance, who ate and drank with him after he rose from the dead. He commissioned us to preach to the people and to testify that he is the one appointed by God as judge of the living and the dead (Acts 10:41 to 42).
Note that Jesus did not appear openly to all but rather only to some. Why is this? It is so different from what most of us would do.