After His death on the cross, Jesus really, truly came back to life. This is not some sort of myth or symbol. Jesus physically rose from the dead and many people saw Him and touched Him.
After Jesus died and was buried, three women went to His tomb to anoint His body with spices. As they approached the tomb, they worried about how they would get past the huge stone that blocked the entrance. They weren’t expecting Jesus to rise from the dead.
In Mark 16:4-6, we read: "But when they looked up, they saw that the stone had been rolled away—for it was very large. And entering the tomb, they saw a young man clothed in a long white robe sitting on the right side; and they were alarmed. But he said to them, 'Do not be alarmed. You seek Jesus of Nazareth, who was crucified. He is risen! He is not here. See the place where they laid Him.'"
Jesus also appeared to Mary Magdalene, two disciples walking on the road to Emmaus, Peter, the eleven original disciples, a crowd of 500, James, and Paul. All of these people were convinced through and through that they had seen the risen Christ.
The disciples openly exclaimed, “Listen, we have seen Him! We have touched Him!” And they died as martyrs: tortured, persecuted, burned at the stake, torn apart by lions. Hypocrites and martyrs are not made of the same stuff. People tell lies to get out of trouble, not into trouble. Few will die for what they know is a lie.
They persisted in their faith because they knew Jesus was really alive.