In 2 Samuel 12:23, David speaks about his dead 7-day-old child, “But now that he is dead, why should I fast? Can I bring him back again? I will go to him, but he will not return to me.” This verse implies that David believes he will see his child again in the afterlife, in Heaven. But why does David have this confidence?
Many Christian theologians have argued for a concept called the age of accountability. The idea is that any person who dies before they are old enough to know the difference between right and wrong, good and evil, goes to Heaven. What biblical evidence do they give for the age of accountability? Norman Geisler and Tom Howe, in When Critics Ask: A Popular Handbook on Bible Difficulties, provide the scriptural basis:
First, Isaiah 7:16 speaks of an age before a child is morally accountable, namely, ‘before the child shall know to refuse the evil and choose the good.’ Second, David believed in life after death and the resurrection (Ps. 16:10–11), so when he spoke of going to be with his son who died after birth (2 Sam. 12:23), he implied that those who die in infancy go to heaven.
Third, Psalm 139 speaks of an unborn baby as a creation of God whose name is written down in God’s ‘book’ in heaven (vv. 14–16). Fourth, Jesus said, ‘Let the little children come to Me, and do not forbid them; for of such is the kingdom of God’ (Mark 10:14), thus indicating that even little children will be in heaven.
Fifth, some see support in Jesus’ affirmation that even ‘little ones’ (i.e., children) have a guardian angel ‘in heaven’ who watches over them (Matt. 18:10). Sixth, the fact that Christ’s death for all made little children savable, even before they believed (Rom. 5:18–19).
Finally, Jesus’ indication that those who did not know were not morally responsible (John 9:41) is used to support the belief that there is heaven for those who cannot yet believe, even though there is no heaven for those who are old enough and refuse to believe (John 3:36).