(The following email was sent in from a former Jehovah’s Witness.)
As I’m sure you are aware the JW doctrine relies heavily upon the incorrect date of 607BCE for the Destruction of Jerusalem (taken from the Millerite movement). As opposed to many indications it cannot possibly be this date. How nice it would be to disprove this from their own bible without needing additional literature, at which they refuse to look.
1) Ask a JW to please read Zechariah 1:12
The Angel requests how long YHWH will not show mercy to Jerusalem and Judah whom He has denounced these seventy years.
2) Ask what the date of destruction was. They always reply 607.
3) Then request they turn to the back of their bible, and give the date when their bible says (correctly) that the book of Zechariah was written. They will reply 518 - 520BCE.
4) Request the witness to do some simple mathematics asking, what is 518/520 added to 70. The obvious answer is 588/590 maximum. (As we know due to regnal years etc. the closest date and correct date is 587/588)
5) Ask them, if the teaching concerning 607 by the faithful and discreet slave is true, how can the bible they carry deny it!!!
If nothing else, it will cause a severe doubt of the date, which holds all things together for the JW’s. I can also tell you they do not have one book which deals with this problem, and have even gone as far that in most of their bibles there is no cross reference to this scripture. This scripture is the one that blew it wide open for me and started me searching for truth and the path out.