In the Gospel for the Second Sunday of Easter Jesus commissions the disciples to continue his work. They are to continue to proclaim the Good News of God's mercy and love.
Thomas wasn't present when Jesus appeared to his disciples the first time. He had some doubts about Jesus appearing to the other disciples. Thomas sought some proof or evidence. Thomas received the evidence he sought. Jesus comes to them once again, Thomas responds by saying, "My Lord and my God." We may sometimes entertain doubts, but reception of the Eucharist is our evidence that Jesus is risen, Jesus lives.