How do we know if someone is a true preacher?

True preachers of the Gospel proclaim the complete truth about God, humanity, sin, and salvation through Jesus Christ. In Matthew 7:20, Jesus indicates that we will recognize them by their fruits, which includes both their personal life and their teaching. A true preacher emphasizes Christ's substitutionary death, the justice of God, and salvation by grace alone, reflecting a deep understanding of Scripture. Therefore, evaluating what they preach about the fundamental truths of the faith is essential in knowing whether they stand firm in the Gospel.