1 Peter 2:4-8 (ESV)
As you come to him, a living stone rejected by men but in the sight of God chosen and precious,  you yourselves like living stones are being built up as a spiritual house, to be a holy priesthood, to offer spiritual sacrifices acceptable to God through Jesus Christ.  For it stands in Scripture:
"Behold, I am laying in Zion a stone,
a cornerstone chosen and precious,
and whoever believes in him will not be put to shame."
 So the honor is for you who believe, but for those who do not believe,
"The stone that the builders rejected
has become the cornerstone,"
"A stone of stumbling,
and a rock of offense."
They stumble because they disobey the word, as they were destined to do.
“They stumble because they disobey the word, as they were destined to.” I am reading the Greek, the word “because” doesn’t seem to be in there. In fact, it seems this should read “they stumble by disobeying the word to which end they were appointed.” Not sure how much difference it makes. But then again, sometimes a small nuance like that makes a big difference. It isn’t that they disobey the word and then stumble. It is they stumble in not obeying it. And here it is disobey, but I think in the sense of refuse to listen to it. They refuse to listen to the gospel and in so doing they stumble, and this was appointed. Why? I don’t know. Perhaps because they were just incapable of doing anything else, here though we try to pry into the mind of God and receive answers we will never have to questions we might not ask in the first place.
I don’t know why it is some people here and believe, and some hear and don’t. I know that those who are saved are saved of God, and those who are not can blame themselves for their own hard hearts. Of course if they don’t hear at all, then perhaps that is my fault. But it is precisely in rejecting the word, in not listening to it, not heeding it, that they stumble that is fall. In refusing to listen they lose salvation, and it is not God’s fault that they cling to sin, but their own. God would have all men to be saved. They are the ones who refuse to listen, God will let them stumble then.