Let us consider how we might rank the different divine manifestations that men have enjoyed for just a moment. Here are a few random ones:
Daniel heard the voice of the Lord speaking to him.
Peter saw a vision of a net of animals descending from heaven.
Christ visited the Nephites for three days and then returned to visit them "oft" for some period of time.
Isaiah saw the Lord in vision.
Lehi had a vision in which he saw the tree of life and was given instruction.
The Holy Ghost revealed the true meaning of James 1:5 to Joseph Smith.
Angel Moroni appeared repeatedly to Joseph Smith one night
The Holy Ghost descended in the sign of the dove at Christ's baptism, and the Father spoke briefly from heaven.
But here is the point. Add one more item to the list:
Living for all eternity in the presence of the Father and the Son.
Can we not see that this last one is simply on a wildly different scale of spiritual experience than all of the others? And we have this bizarre idea that, with no particular effort, we will enjoy this last one for all eternity and at the same time believe we can think of all the others as nothing more than unimportant gospel perks.
We should at least recognize that the smaller experiences that are practically nothing compared to living in the presence of the Father and the Son for eternity are PREPARATORY. They are much smaller, much lesser, tiny manifestations compared to the one we all actually want to have.
If our goal is the Mount Everest of spiritual experiences, namely, to live for eternity in the presence of God, then we should not be surprised that along the route there are lesser things that mark the way and prepare us.
Now, covering the whole distance in mortality to that final experience simply isn't going to happen. So how far along the road does God require us to make it in mortality? That is far more than I know. I could not possibly answer.
But I think it is important to realize that we don't just die and skip ahead to the top of the Mount Everest of spiritual experiences without having started down the path. The gate onto the path is marked by baptism and the gift of the Holy Ghost. The Holy Ghost is a revelator. Thus, the gate onto the path gives us the companionship (insofar as we are worthy) of a God who knows all things. Joseph Smith said:
No man can receive the Holy Ghost without receiving revelations. The Holy Ghost is a revelator.
Thus the gate onto the path starts with revelation. The path is defined by revelation. We can not trod far onto that path without learning to receive revelation. In fact, we cannot really even begin without a revelation that is commonly called a "testimony". But that is the seed that is intended to grow into the full tree. The full tree it is intended to grow into is the final experience of living with the Father and the Son for eternity.
But it must grow into it. We cannot skip ahead. We must simply press forward along the path doing what is right, and particularly striving to save the souls of men, including our dead, as directly as we know how. It is up to God on when he grants his graces to mankind. Forcing revelation is asking for trouble. We must learn to grow into it instead, letting God grant his saving graces to us how, and when he sees fit.
But in time, or in eternity, we must receive those saving graces which lead us up if we are to gain exaltation. There is no alternative. Man cannot be saved in ignorance. We cannot possibly learn to live so that we can be with the Father and the Son for all eternity before we have learned to so that God will grant to us the much lesser, much smaller, rights of the priesthood.
D&C 107:18 The power and authority of the higher, or Melchizedek Priesthood, is to hold the keys of all the spiritual blessings of the church—
19 To have the privilege of receiving the mysteries of the kingdom of heaven, to have the heavens opened unto them, to commune with the general assembly and church of the Firstborn, and to enjoy the communion and presence of God the Father, and Jesus the mediator of the new covenant.
20 The power and authority of the lesser, or Aaronic Priesthood, is to hold the keys of the ministering of angels, and to administer in outward ordinances, the letter of the gospel, the baptism of repentance for the remission of sins, agreeable to the covenants and commandments.
These, manifested through the gift of the Holy Ghost, are the graces we are to be saved by. This is wherein Christ progressed from grace to grace until he received a fullness. How far we need to get in mortality is far more that I can say. But it is important that you and I both recognize the tenuous position of casually and happily living far beneath our privileges. For we all do so in this age, and it is a dangerous business. We should recognize the path that is laid out before us, so we stop thinking that we are on heaven's doorstep just because we are nigh unto death and start pressing forward more diligently that we may prove worthy of the prize.