Most of the conversations I have had with people regarding a "mediator" usually ends up with people talking about a catholic priest being a mediator. People get this impression because they feel when they confess to a priest and they go before God that they are acting as a mediator. The question I brought up and was in agreement with while chatting with a few musicians. Are we missing the biggest mediator of all? Denominations.
When a person feels God has spoken to them about something, inevitably we run it through our denomination filter. If it lines up with what "they" believe...then in must be a God thing. If it does not line up with it...then it needs to go. This is not to say that some denominations offer GREAT flexibility. None the less when you are raised with a certain belief system and God speaks to you to do something outside of that system...we think "surely this cannot be of God." This can prevent churches and people from doing ministry because if God has spoken to them about something and it does not line up with what their denomination believes than nothing gets done.
So...mediator? Person or denomination or both?