John 20:24-29 (NLT)
One of the twelve disciples, Thomas (nicknamed the Twin),1 was not with the others when Jesus came. They told him, “We have seen the Lord!”
But he replied, “I won’t believe it unless I see the nail wounds in his hands, put my fingers into them, and place my hand into the wound in his side.” Eight days later the disciples were together again, and this time Thomas was with them. The doors were locked; but suddenly, as before, Jesus was standing among them. “Peace be with you,” he said. Then he said to Thomas, “Put your finger here, and look at my hands. Put your hand into the wound in my side. Don’t be faithless any longer. Believe!” “My Lord and my God!” Thomas exclaimed. Then Jesus told him, “You believe because you have seen me. Blessed are those who believe without seeing me.”


1 Corinthians 15:14 (ESV)
And if Christ has not been raised, then our preaching is in vain and your faith is in vain.