This isn't Jeopardy but - a gold star to the first person who answers correctly *S* Where is this quote from?

"Painted on one side of our Sunday School wall were the words, God Is Love. We always assumed that these three words were spoken directly to the four of us in our family and had no reference outside, which my brother and I soon discovered was full of bastards, the number increasing rapidly the farther one gets
from Missoula, Montana."