If the resurrection didn’t happen, forget Christ and Christianity. Since it did happen, everything Jesus said, taught, and did are true. Eye witness testimony is helpful in court. Many eye witnesses to one event is better. Large groups of people may see different aspects of an event from their perspective (Like the crucifixion accounts in the Gospels), but affirmation of an event is the point. Hundreds of people do not have the same hallucination. This is the reason Paul wrote the following about Jesus’ resurrection in 1 Cor 15:3-6…
For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, that he was buried, that he was raised on the third day in accordance with the Scriptures, and that he appeared to Cephas, then to the twelve. Then he appeared to more than five hundred brothers at one time, most of whom are still alive, though some have fallen asleep.
Paul wrote, “Most of whom are still alive” for a reason. You could have gone and asked them yourself about Jesus being alive. You could talk to 10, 100, or 200 who were all at the same place at the same time when Jesus appeared. There was no doubt Jesus died and there is no doubt Jesus is alive. It is a historical fact whether people believe it today or not.
Am I sure Jesus is alive? Yes. How? By faith. Thomas was told Jesus was risen from the dead, but he refused to believe unless he saw Jesus for himself. Then it is recorded in John 20:26-29…
Eight days later, his disciples were inside again, and Thomas was with them. Although the doors were locked, Jesus came and stood among them and said, “Peace be with you.” Then he said to Thomas, “Put your finger here, and see my hands; and put out your hand, and place it in my side. Do not disbelieve, but believe.” Thomas answered him, “My Lord and my God!” Jesus said to him, “Have you believed because you have seen me? Blessed are those who have not seen and yet have believed.”
Every Christian today falls into the category of believing but yet not having seen with physical eyes. Jesus’ resurrection isn’t true because I believe it, I believe it because it is true.