It is noteworthy that neither James nor any of the other brothers of Jesus believed in Him prior to His resurrection. In fact, at one point, they even came to take Him home, thinking He had taken leave of His senses. John 7:5 tells us, "For even His brothers did not believe in Him."
James starts his epistle by identifying himself as a servant of our Lord Jesus Christ (James 1:1). This is significant when you consider the fact that James had the distinction of being the half-brother of Jesus. We know Jesus had other brothers and sisters. Yet it is interesting that James does not begin his epistle by saying, "James, the brother of the Lord," or even, "James, the half-brother of Jesus." Instead, he writes, "James, the servant of Jesus."
Here was Jesus who lived a flawless life, a sinless life. He never lied or stole or lost His temper. He never even sinned inwardly. Yet as Jesus himself said, "A prophet is not without honor except in his own country, among his own relatives, and in his own house" (Mark 6:4). That just goes to show that even living a perfect and sinless life will not necessarily convince someone. And all of us have fallen short at times in living out the witness we ought to live.
The hardest people to reach are often those who are closest to us, especially in our own families. Many of us were raised in non-Christian homes. We know how difficult and hostile an environment that can be. It took the resurrection of Jesus Christ from the dead to finally reach His brothers. That is when they all believed. It took the power of the gospel.