Now go and tell his followers. And be sure to tell Peter. Tell them, ‘Jesus is going into Galilee and will be there before you come. You will see him there, as he told you before.’”
This was after his death, but he showed them that he was alive, proving it to them in many ways. The apostles saw Jesus many times during the 40 days after he was raised from death. He spoke to them about God’s kingdom.