Why did those babies who died in the womb, die?
Because of the curse. Adam's sin did bring a curse upon the whole world. God said man would return to the dust from which he came. But all of creation is cursed, things grow old and wear out, even animals that cannot sin die.
Will they need to be born again to enter the kingdom of God, that is eternal life.
I do not believe Jesus was speaking of little babies and small children, but of men who have reached the age of accountability. The Jews to this day do not believe children are accountable before God until they learn the law.
Men need to be born again because they have spiritually died. Little babies and children have not sinned and spiritually died.
Paul shows this in Romans 7. He tells of when he learned the law. He would have not known sin except for the law. Then Paul tells us he was ALIVE without the law ONCE. He was not spiritually dead, he was not separated from God by sin.
Rom 7:7 What shall we say then? Is the law sin? God forbid.
Nay, I had not known sin, but by the law: for I had not known lust, except the law had said, Thou shalt not covet.
8 But sin, taking occasion by the commandment, wrought in me all manner of concupiscence. For without the law sin was dead.
9 For I was alive without the law once: but when the commandment came, sin revived, and I died.
10 And the commandment, which was ordained to life,
I found to be unto death.
11 For sin, taking occasion by the commandment, deceived me, and by
it slew me.
Paul cannot possibly be teaching he was physically dead here. He is teaching that he was spiritually alive, but when he learned the law he became accountable. Sin used the law against him to convict him of sin and kill him. He thought the law would lead to life, but instead it lead to his death.
This scripture is very plain and not complicated to understand. Paul is clearly teaching he was not spiritually dead until he learned the law. Without the law, sin is dead, it has no authority or power over anyone. Without law sin is not imputed.
That is why eating from the tree of knowledge and good and evil spiritually killed Adam and Eve. The moment they understood right from wrong they were convicted of their sin and died.
And a certain ruler asked him, saying, Good Master, what shall I do to inherit eternal life? Luke 18:18 Equating inheriting to entering the kingdom of God. V25 For it is easier for a camel to go through a needle's eye, than for a rich man to enter into the kingdom of God. and V30 Who shall not receive manifold more in this present time, and in the world to come life everlasting
To inherit or merit eternal life you must obey the law PERFECTLY your entire life. If you sin even once, you are guilty of breaking all the law, and the wages of sin is death.
Jam 2:10 For whosoever shall keep the whole law,
and yet offend in one point, he is guilty of all.
This is why the scriptures say there is none that do good, no, not one. It is speaking of 100% sinless perfection. To be "good" you have to be absolutely sinless like God himself. This is why the scriptures say "for all have sinned and come short of the glory of God"
It is not saying that men cannot do good things. When you tell the truth, that is good, that is obeying God's law. But you must be perfectly good to merit or inherit eternal life. Only Jesus has done this.
