So the other disciples told him, 'We have seen the Lord!'  But [Thomas]
said to them, 'Unless I see the nail marks in his hands and put my finger
where the nails were, and put my hand into his side, I will not believe
it.'....
Then [Jesus] said to Thomas, 'Put your finger here; see my hands. Reach out
your hand and put it into my side. Stop doubting and believe.'" Thomas said
to him, 'My Lord and my God!'"
John 20:25, 27-28 (NIV)

Jesus wasn't hard on Thomas for his doubts. Despite his skepticism, Thomas
was still loyal to the believers and to Jesus himself. Some people need to
doubt before they believe. If doubt leads to questions, questions lead to
answers, and the answers are accepted, then doubt has done good work. It is
when doubt becomes stubbornness and stubbornness becomes a life-style that
doubt harms faith. When you doubt, don't stop there. Let your doubt deepen
your faith as you continue to search for the answer.