1 Bible Verses about Apostasy in OT

In that it is said, This day if you hear his voice, harden not your hearts, as in the provocation: for who were those, having heard, who were hardened? yea, were they not all those having come out of Egypt under Moses? And 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 who believed not? And we see that they were not able to enter in on account of their unbelief.