1 Bible Verses about Apostasy in OT

In the words of Scripture, Today, if you hear his voice, Do not continue to harden your hearts as at the Provocation. For who were they that heard and yet provoked him? Was it not all who came out of Egypt under the leadership of Moses? And with whom was he grieved for forty years? Was it not with those who had sinned, and whose dead bodies fell in the wilderness?read more.
And to whom did he swear that they should never enter into his rest, if not to those who had proved faithless? So you see that it was through unbelief that they were not able to enter in.