Mouthpiece of God

I can't help but see preaching as being God's mouthpiece. That's a bit unnerving. It causes me to have others look over what I have written in notes.

I always pray before I prepare a sermon. I ask God to guide me. I ask godly people their thoughts on the message. I pray more as I internalize the message.

All those things ease my mind. But should I be at ease? I think not. Confident? Perhaps, if that confidence is produced from reliance on, and faith in God.

Acts 1:8 says "But you will receive power when the Holy Spirit comes on you; and you will be my witnesses in Jerusalem, and in all Judea and Samaria, and to the ends of the earth." 
Here I am, at the end of the earth, praying, "Holy Spirit, give me powerful words."