How does the Bible define effective preaching?

In the context of 2 Corinthians 4, effective preaching is characterized by a reliance on the sufficiency of God rather than human ability. Paul states that he is not sufficient in himself, indicating that true effectiveness comes from God alone. The preaching of the gospel is meant to be a public declaration of Christ, declaring His work of salvation. When delivered faithfully, the Holy Spirit uses this truth to convict hearts, leading to repentance and faith. It draws individuals toward the light of the knowledge of the glory of God found in Christ, fulfilling the purpose of ministry.