Okay, here's another lost song with that phrase. I think it is called "It's Gonna Rain" and the onliest verse that I can remember is:

Its gonna rain, its gonna rain,
Oh you better get ready, and keep this in mind;
When God gave Noah the Rainbow sign he said,
"It won't be water, but fire next time."

I just remember that we used the song with our puppet group. The version we used had a killer bass that rumbled out the "it won't be water but fire next time" and when used with the puppets it had the audience in stitches (I'm not quite sure that was the song's original intention.)

Does anyone have the rest of the words?

Freightdawg