Answer:
They believed it would lead their people to disaster.
A good place to read the answer for yourself ... so that you don't have to rely on
anyone else's translation or interpretation for your own understanding ... is in the
text of the premier edition.
Check out Deuteronomy 28:15-68 .
It's impossible for anyone to guess what any individual or group of Israelites believed
3,000 years ago. But at least in that passage you can read exactly what they were told
would happen.