The authority of preaching comes from Christ, who empowers and sends preachers as His emissaries.
The authority in preaching stems not from the individuals who proclaim the Word, but from Jesus Christ Himself, who commissions men to preach the Gospel. In Mark 16:15, Jesus commanded His disciples to go and preach the Gospel to every creature. Furthermore, the ascension of Christ gives authority to preaching because it signifies His exaltation and the sending of the Holy Spirit, as explained in Ephesians 4:8-12. The effectiveness of preaching is rooted in the premise that believers are not just hearing about Christ, but hearing Him, as the Holy Spirit works through their words, making it an operation of grace that leads to faith and conviction.
Scripture References:
Mark 16:15, Ephesians 4:8-12
Commentary