1 Bible Verses about Apostasy in OT

"To-day if ye will hear his voice, harden not your hearts, as in the provocation." For some that heard did provoke; but not all that came out of Egypt with Moses. But with whom was He provoked forty years? was it not with those that sinned, whose carcases fell in the wilderness?read more.
and to whom did He swear that they should not enter into his rest, but to those that were disobedient? and so we see that they could not enter in because of unbelief.