Why do some people fail to believe the gospel?

The failure to believe the gospel often stems from a person's spiritual condition as described in John 10, where Christ states that those who do not believe are not His sheep. This reflects a broader theological understanding that faith is a gift from God, granted only to His elect. While many may hear the gospel, true belief arises from a work of the Holy Spirit in the believer's heart. This doctrine teaches Christians that the response to the gospel is not simply a matter of willpower but inherently tied to God’s sovereign election and grace—showing that belief is rooted in God's initiative.