How do we know that preaching is effective for saving souls?

The effectiveness of preaching in saving souls is rooted in the power of God, as articulated in 1 Corinthians 1:18, which states that the preaching of the cross is the power of God to those who are saved. The Apostle Paul reflects on the contrasting perceptions of the message of the cross—from foolishness to power. For those who are perishing, the message may seem absurd, while for those who are being saved, it reveals the transformative power of God. Preaching directs hearts to see their need for a Savior, demonstrating the inadequacy of human wisdom and the necessity of divine intervention. As the Holy Spirit moves in accordance with the preached Word, believers experience the miraculous work of regeneration, confirming the truth that faith comes by hearing, and hearing by the Word of God (Romans 10:17). Thus, through the faithful proclamation of the Gospel, individuals are called out of darkness into the light of Christ.