Bible Verses About Preaching: Moses, slow of speech

And Moses saith unto Jehovah, `O, my Lord, I am not a man of words, either yesterday, or before, or since Thy speaking unto Thy servant, for I am slow of mouth, and slow of tongue.'

And Jehovah saith unto him, `Who appointed a mouth for man? or who appointeth the dumb, or deaf, or open, or blind? is it not I, Jehovah?

and now, go, and I--I am with thy mouth, and have directed thee that which thou speakest;'