I heard this 20 years ago from someone, who was NOT the author. Thanks for your help.
Here are some lyrics:
Moses,
Saw some smoke
Came to the bush
And the bush was burnin'
Take off your shoes, Moses,
You're on holy ground
Moses, I want you to be my man
Moses, way down in Egypt-land
Moses, I want you to work for me
Moses, I want you to set my people free
Not me, Lord
I,I,I, don't talk so good
I studddddder all the time
Do you know my brother Aarron?
He can sing like an angel
Talk just like a preacher
Not me, Lord...