James, the brother of Jesus wasn’t a follower of his half brother until after His resurrection. I guess all doubts James may have had about Jesus disappeared when He went from dead to not dead.
The resurrection matters. Imagine being James and your brother has died and your mother is really upset. Three days later….

The resurrection turned an unbelieving brother into a disciple of Christ. It turned grieving disciples into joyous proclaimers of the good news. Historians recorded that Jesus was executed. But more people saw a resurrected Christ than witness the signing of the US Constitution. 500 people all at once saw Him. It’s a historical fact.
Luke, the physician, was the historian. Here are the facts he recorded:
1On the first day of the week,a very early in the morning, the women came to the tomb, bringing the spices they had prepared.2They found the stone rolled away from the tomb, 3but when they entered, they did not find the body of the Lord Jesus. 4While they were puzzling over this, suddenly two men in radiant apparel stood beside them.5As the women bowed their faces to the ground in terror, the two men asked them, “Why do you look for the living among the dead? 6He is not here; He has risen! Remember how He told you while He was still in Galilee: 7‘The Son of Man must be delivered into the hands of sinful men, and be crucified, and on the third day rise again.’”
Luke 24
Christ is risen! What will you do about that today?