Teaching with a blank slate

When reading about Jedediah's ability to get up and teach from a blank slate really put into perspective what giving a talk in church is about now days. I was given a subject, have the churches website, magazines, etc. He just went with what he had at the time, which was probably his scriptures. He could talk for hours on one subject and have people riveted to the talk. It is hard sometimes to talk for twenty minutes or so. It talked about this on pgs. 32 -34 of Mormon Thunder. I really wish that I had that ability, or even the faith to do this.