How do we know that God uses ministers in the conversion of sinners?

Paul, in Romans 10:14-15, argues that for anyone to call upon the Lord, they must first believe, and to believe, they must hear the gospel. This clearly illustrates God's designed means of using ministers as His instruments for spreading the gospel. The act of preaching is ordained by God as a vital part of His salvific work, making ministers essential to the process of conversion. It underscores the responsibility of those called to proclaim the truths of God's Word and the importance of hearing the gospel for saving faith.