My people are destroyed for lack of knowledge: because thou hast rejected knowledge, I will also reject thee, that thou shalt be no priest to me: seeing thou hast forgotten the law of thy God, I will also forget thy children (Hosea 4:6).
This grave judgment spoken almost three thousand years ago reflects a timeless principle that is just as applicable today. When people die without being saved, it is not that God did not want them to be saved, for He would have all men to be saved, and to come unto the knowledge of the truth (I Timothy 2:4). He is not willing that any should perish, but that all should come to repentance (II Peter 3:9).
The problem is that, when men lack the knowledge that would bring them to Christ for salvation, it is because they have already rejected knowledge that would have led them to the knowledge they need. Paul writes that, in the last days, men would be ever learning, and never able to come to the knowledge of the truth (II Timothy 3:1,7). And the next verse tells why. It is because they resist the truth (II Timothy 3:8). They shall turn away their ears from the truth, and shall be turned unto fables (II Timothy 4:4).
Peter says that those who question Gods Word in favor of an assumed naturalistic view of history willingly are ignorant (II Peter 3:5), and Paul says that if they refuse to see the evidence of the Creator in His creation, they are without excuse (Romans 1:20). Whether or not they have read Gods Word, they have an intuitive knowledge of God and His law in their consciences (Romans 2:15), with their thoughts accusing or else excusing one another.