1 Bible Verses about Apostasy in OT

So while we can still speak of Today, if you hear him speak, do not harden your hearts, as they provoked him by doing. For who was it that heard him speak and yet provoked him? Was it not all those who had escaped from Egypt under Moses' leadership? And who was it with whom God was angry forty whole years? Was it not with those who had sinned, who dropped dead in the desert?read more.
And who was it to whom God made oath that they should not be admitted to his Rest, if it was not to those who had disobeyed him? So we see that it was their unbelief that kept them from being admitted to it.