What does the Bible say about Paul's authority as an apostle?

In the sermon, it is emphasized that Paul's authority to preach the gospel is derived solely from his encounter with Jesus Christ on the road to Damascus, affirming that he is an apostle by God's calling. The text highlights that all true preachers receive their authority from God, as is evidenced in Paul's unwavering commitment to preach Christ and Him crucified. This divine origin of authority is crucial to understanding the authenticity of Pauline doctrine, especially in his correction of false teachings.