Why do some people not believe in God despite evidence?

The struggle of unbelief is a central theme in Scripture, reflecting the reality that not all who hear the gospel will believe. As seen in the story of the rich man, even an extraordinary event such as someone rising from the dead would not guarantee belief for those who are resistant. Abraham reminds the rich man that his brothers have the Scriptures (Moses and the prophets) which should be sufficient to lead them to repentance. True faith and repentance are gifts from God, as stated in Acts where it is noted that God granted repentance to the Gentiles. This divine work in the heart is essential, as it opens one's eyes and enables them to see the truth of the gospel and respond in faith.