Matt 19:9

The sense of the "me epi porneia" in Matt 19:9 is not a real problem, even
if you translate it woodenly:  Whoever puts away his wife not for porneia and
marries another commits adultery".  That is, if the divorce is not on the 
grounds of porneia, but for the convenience of the man, the subsequent 
marriage is in fact adultery.  Now the real question in Matt 19:9 is what
was the original sense of porneia?  The term is translated variously as 
"fornication" or "adultery" but is cognate with the term porne (prostitute).
But J. A. Fitzmyer (in an article a couple of decades ago in Theol. Studies)
argued that behind the term here is the Hebrew term zenuth, which covers
marriages within forbidden degrees of blood relationship (see e.g. Lev 18),
and that the porneia here refers to Gentile marriages with near relatives
that would be unacceptable to Jewish Christians.  So, Matt 19:9 is an
adaptation (on this view) of a dominical saying to make it fit a special
situation in an early mixed Jewish-Gentile Christian congregtion.  I'm away
from my files just now on sabb. leave and working on other things, but 
Fitzmyer's article could be easily found, and perhaps others may have other
material to bring to bear.  Larry Hurtado, Robinson College (lwh11@phx.cam.ac.