http://www.youtube.com/watch?v=y80FK6e4uBE

This video is an excerpt from a message by pastor and author John Piper.  He is one of my favorite communicators. The purpose of this particular portion of the message was to explain what salvation truly is.  The audience was thousands of college students at a conference in Atlanta called Passion.

He effectively used logos by discussing multiple things that salvation is not to help explain what it is.  He also used it by walking the audience through how they could logically discern whether they had experienced true salvation.

Given his topic and audience, he had really strong ethos.  Almost everyone at the conference would have read his books or heard his sermons. This gave the words he was saying a lot of credibility.

He used pathos by saying that salvation would give you new desires and new sources of pleasure.  He explained that these new desires cause people to find the deepest joy possible in salvation and the life that follows it.  

His combination of logos, ethos, and pathos made him effective in achieving his purpose of explaining what salvation truly is.