John 20:19-29 (New International Reader's Version)
19 On the evening of that first day of the week, the disciples were together. They had locked the doors because they were afraid of the Jews.
Jesus came in and stood among them. He said, "May peace be with you!" 20 Then he showed them his hands and his side. The disciples were very happy when they saw the Lord.
21 Again Jesus said, "May peace be with you! The Father has sent me. So now I am sending you." 22 He then breathed on them. He said, "Receive the Holy Spirit. 23 If you forgive anyone's sins, they are forgiven. If you do not forgive them, they are not forgiven."
24 Thomas was one of the Twelve. He was called Didymus. He was not with the other disciples when Jesus came. 25 So they told him, "We have seen the Lord!"
But he said to them, "First I must see the nail marks in his hands. I must put my finger where the nails were. I must put my hand into his side. Only then will I believe what you say."
26 A week later, Jesus' disciples were in the house again. Thomas was with them. Even though the doors were locked, Jesus came in and stood among them.
He said, "May peace be with you!" 27 Then he said to Thomas, "Put your finger here. See my hands. Reach out your hand and put it into my side. Stop doubting and believe."
28 Thomas said to him, "My Lord and my God!"
29 Then Jesus told him, "Because you have seen me, you have believed. Blessed are those who have not seen me but still have believed."
Doubts. We all have had them. Especially about the story of Jesus. It is hard to believe that God came as a man and died for our sins on the surface. It seems inplausable that someone would do that for us. Let's face it, believing in Jesus Christ and placing your eternal faith in Him is difficult to do. It just doesn't make sense, that the God of the universe would thing so highly of us, as to sacrifice His Son for us.
For the disciples, no matter how many times Jesus told them, not one of them had the faith to believe that Jesus would do what He said He would do; die and come back in three days. The events from the arrest to the crucifixion all happened so fast, that they didn't have time to think. Instead it was easier to run away and hide. Only John had the nerve to even be there when He died. For their doubts to become belief they would have to see the risen Jesus Christ, but for Thomas, he had to take it a step further and touch him.
Doubts? It's only natural, because without doubts you can't have faith. What secures my faith and quells all doubts has been the supernatural change God has done in my life, through Jesus Christ. For me it all made sense and by God's grace, I grow every day. Yes, still faced with a few doubts, but now they are just opportunities to grow in my faith.
If you have doubts, it's normal. It means you too are growing in your faith. But, if you have unbelief, and would rather just deny it all happened, then it's time you study the facts for yourself. Your eternity will depend on it.
Painting Incredulity of St. Thomas, by CARAVAGGIO, 1602-03, Oil on canvas, Sanssouci, Potsdam, Germany