I wish I did. This came via e-mail from a friend (sans reference). I can't find a reference on the net, but the placement of the ". . ." spacers in the quote lead me to believe that this may be a compilation of more than one quatrain (perhaps even from more than one century).

Thus, I, too, am somewhat suspect of the accuracy, . . . . but, then again, the prophet has quite a track record to precede him.