Well, actually I have taught it to 5 year olds, and 13 year olds.
FAITH:
Faith is an action --- it's not a feeling.
You get to a supermarket and desire to go in the entrance. There's an escalator you have to take.
You have to GET ON the escalator to go up. You have to have faith that it will take you up.
If you have faith in Jesus, you have to do what He said to do to get you where you want to do.
He said He was preparing a place for you. He said if we're friends we'll do what He said.
I fail to see the problem with this.
BELIEVE:
To believe someone is to have faith in them, it's to know that what they are saying is true, it's to look up to them, to understand what they're saying and to accept it with both your heart and your mind. If we believe someone we want to follow them, we want to know what they teach, we agree to it, we do it.
This is faith, and this is believe.
Either one demands that we follow what Jesus taught.
And stop worrying about why we're doing it.
And stop saying that all we need is faith; this is not so.
We need to FOLLOW Jesus, we need to be disciples, we need to have faith in Him and to believe Him.
Peter, Andrew, John, all the Apostles LEFT EVERYTHING to follow their Lord.
This is how much trust and belief and faith they had in Him.
And we have trouble just saying that we "work" because He instructed us to.