What does the Bible say about the necessity of gospel conversion?

The necessity of gospel conversion is underscored in various Scriptures, which indicate that God has ordained the preaching of the gospel as the means through which the elect come to faith in Christ. Passages like John 17:20 suggest that those who believe do so through the message brought forth by the apostles, affirming that faith is not exercised in a vacuum but is rooted in the revelation of the gospel. Romans 10:14-15 further clarifies this by stating that individuals cannot call upon Christ unless they believe, and they cannot believe without hearing the gospel preached by those sent by God. This reflects the biblical principle that while salvation is entirely of grace, God has sovereignly chosen to utilize means, specifically the proclamation of the gospel, to bring His elect to the knowledge of Christ and their subsequent faith in Him.