I've just written a small note of encouragement to someone about getting up in front of a group of people and giving a devotional talk. I think that the most classic example of this was Mr Bullrush himself, Moses.
One of the most famous stories of the Old Testament was when God spoke to Moses out of a burning bush and told Moses in an audible voice what He wanted of him. What was Moses' reaction?
"O Lord, please send someone else to do it." Exodus 4:13
Even though God told Moses that He would be with him and would help him, Moses didn't want to do it. Now it is important that we put this in the proper perspective. Moses was saved by the Hand of God when he was a baby. God arranged for Moses to be raised and educated as a son of Pharaoh's daughter. This meant that Moses had all the benefits of the best education of the Egyptians, he understood the form of government Egypt was under. He knew how things worked. Now God was asking him to go back to Egypt and confront Pharaoh about the Israelites. Moses was the man who was best qualified to do this job.
Moses had a lot of reasons for asking God to send someone else, just look:
Moses said to the LORD, "O Lord, I have never been eloquent, neither in the past nor since you have spoken to your servant. I am slow of speech and tongue." The LORD said to him, "Who gave man his mouth? Who makes him deaf or mute? Who gives him sight or makes him blind? Is it not I, the LORD? Now go; I will help you speak and will teach you what to say." Exodus 4:10-12
God sent Aaron to help Moses. The truth in point is that throughout the rest of Exodus, Moses does most of the talking himself, despite his lack of eloquence and slowness of speech. Even though he probably got tongue tied, God used Moses anyway.
The point of all of this is that you don't need to be Master of the Press Club, God still uses schmoes and busboys as He sees fit.