How do we know a preacher is truly sent by God?

The Apostle Paul outlines the characteristics of a true preacher in 1 Thessalonians 2, where he emphasizes their boldness in God and the purity of their motives. True preachers do not seek to please men but aim to deliver God's message with integrity. They endure persecution and do not engage in deceitful tactics. This commitment to truth and the gospel’s content is critical, as it reflects their divine calling and sincerity in ministering to others, ensuring their ministry is not in vain.