Some popular prophecy scholars teach that children will be included in the rapture regardless of whether they are believers or not. What scriptural basis is there for this? What is the age / event at which a child becomes old enough to be responsible for their own beliefs?
The scriptural basis is found in Matthew 18:10-11:
“See that you do not look down on one of these little ones. For I tell you that their angels in heaven always see the face of my Father in heaven.”
Paul alluded to this when he wrote “Once I was alive apart from law; but when the commandment came, sin sprang to life and I died.” (Romans 7:9)
He was saying that before the age of accountability he was not responsible for his sins, and had eternal life. But once he came of age he was responsible, and became subject to death.
In the Jewish culture the age of accountabililty was 12-13. There is no such clarity where the Church is concerned. I’ve assumed that means that it’s different for everyone, and accountability comes when a child is old enough to understand the concepts of sin and salvation and make an informed decision to accept or reject the Lord’s offer of pardon.