Heaven and Hell - Yes
Damnation for 6 year olds -No
As most of you know, I'm LDS (Mormon). From what I understand of other faiths, we have a unique view on salvation as it relates to young children.
While it is true children can be mischievous and in some instances down-right evil, Satan has no power to tempt them until they begin to become accountable. (Doctrine & Covenants 29:46-47). That means they have no reason to repent or be baptized until they reach the age of accountability. That has been determined to be 8 years old. (D&C 68:25-27) Why 8? I don’t really know; although studies have shown that that is the age at which most children really begin to understand the concept of right and wrong and are capable of making choices based on their own reasoned thoughts. At any rate, all children who die before the age of accountability are saved in the celestial kingdom. (D&C 137:10)
It should probably also be mentioned “that men will be punished for their own sins, and not for Adam’s transgression.” (Article of Faith 1:2) Essentially, that means that I reject the concept of original sin. Our revelation says: “Every spirit of man was innocent in the beginning”—meaning that spirits started out in a state of purity and innocence in preexistence—“and God having redeemed man from the fall, men became again, in their infant state, innocent before God” (D&C 93:38)—meaning that all children start out their mortal probation in purity and innocence because of the atonement. Our revelations also say, “The Son of God hath atoned for original guilt, wherein the sins of the parents cannot be answered upon the heads of the children, for they are whole from the foundation of the world.” (Moses 6:54.)
To address other concerns expressed in this thread, additional explanation seems necessary. This issue directly relates to what happens to us when we die.
We're told several times in the scriptures that faith in Christ is essential for salvation. We also believe we have to show our faith by our works. (See James 2:17-18). One of the ways in which we do this is by following Christ's example and being baptized, but I’ll come back to that in a second.
The fall of Adam and Eve created two distinct kinds of death: spiritual and physical. Physical is obvious – we all die. Spiritual death is the separation from God we experience when we sin. Christ’s atonement unequivocally overcame the physical death through his death and resurrection. All will be resurrected regardless of their level of righteousness (whatever you consider to be righteousness).
“And though after my skin worms destroy this body, yet in my flesh shall I see God:” (Job 19:26)
Each individual can also be saved from spiritual death as well by the grace of God, through faith in Jesus Christ. This faith is manifested in a life of obedience to the laws and ordinances of the gospel and service to Christ.
When we die, our physical bodies are separated from our spirits (souls?). Our physical body is obviously discarded in whatever manner is chosen, but our spirits go to what is probably most easily described as a waiting room as they await their resurrection and final judgment. There is a separation between those who accepted the gospel and those who have not. Essentially, there’s a great deal of missionary work being done so that those who never had the opportunity or those who as of yet have rejected the gospel still have to opportunity to accept or reject Christ as their Savior. It is here that the faith in Christ requirement can be fulfilled by those who haven’t had to opportunity to accept it. (See D&C 138:30-35) This is a natural segue into the doctrine of baptism for (or in behalf of) the dead.
“Else what shall they do which are baptized for the dead, if the dead rise not at all? why are they then baptized for the dead?” 1 Corinthians 15:29
As I’ve already stated, baptism is a requirement for salvation in addition to faith in Christ. Baptism by proxy enables those that have died without having been baptized and no longer have physical bodies with which to be baptized (at least they don’t in their current state) to receive the necessary ordinance of baptism. This is one of the ordinances performed in LDS temples and it is done by the sealing power mentioned throughout the Bible, Book of Mormon, and Doctrine and Covenants. (e.g. Matt. 16:19 – “And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.”)
To be clear, those who die before the age of accountability do not go through this process. They are saved through Christ’s atonement unequivocally. As stated above, they are incapable of sin and therefore have no need to repent and be baptized.
As it relates to Hell, “Hell” is not weeping and wailing and gnashing of teeth because of a literal burning as it seems most here have indicated that it is. Hell is the emotional pain we feel from being separated from God’s presence for eternity. It is a state of mind knowing what could have been had that person been more obedient. Our choices damn us, God doesn't. There is another thread in here where I discuss the concept of degrees of glory, so I won’t make this post any longer by including that here. Sufficient to say, while “Hell” will not be pleasant, it won’t be because those there are being physically tortured.