tattoo,
May I suggest you ask your little bible friend how many secular dates are in the bible? (Answer will be none)
So the next question is .... So how did they come up with 607 BCE????? (Answer some secular authority will be given for the coming back of the Jews on ta certain date)
Next question what do these same secular authorities say about the date of the fall of Jer.?
Just a thought.
I highly recommend you thoroughly research this.
AlanFs stuff is great at ( http://www.geocities.com/osarsif/index2.htm
hawk