D&C 76

In the great vision of degrees of glory, the Prophet explained -

"...being in the Spirit ...By the power of the Spirit our eyes were opened and our understandings were enlightened, so as to see and understand the things of God—"  (Doctrine and Covenants Section 76:11 - 12)

Thus being in the Spirit, having had great things revealed to him, the Prophet records that at the -

"...end of the vision which we saw, which we were commanded to write while we were yet in the Spirit."  (Doctrine and Covenants Section 76:113)

But he also tells us that so  -

"...great and marvelous are the works of the Lord, and the mysteries of his kingdom which he showed unto us, which surpass all understanding in glory, and in might, and in dominion;
115 Which he commanded us we should not write while we were yet in the Spirit, and are not lawful for man to utter;
116 Neither is man capable to make them known, for they are only to be seen and understood by the power of the Holy Spirit, which God bestows on those who love him, and purify themselves before him;
117 To whom he grants this privilege of seeing and knowing for themselves..."  (Doctrine and Covenants  Section 76:114 - 117)

The recorded portion of the revelation is great and marvelous.  Can you imagine that which was shown to the Propeht that was surpassed all understanding.  That is what is available to all men whom  the Lord grants, being in the Spirit,  this great privilege.

Elder Orson Pratt wrote -

"When the time shall come that the Spirit of the living God shall be poured out upon all flesh, in a very few moments of time the Lord could unlock the mysteries and treasures of the earth, so that we could understand not only the geographical surface of the earth, but be able, by the power of vision, to behold every particle of it inside as well as outside, and also the law that governs its elementary portions, nearly all of which is now closed from our mortal vision. We can only go about so far with our natural sight; but there is a faculty in every man and woman which is now sleeping in a dormant state; and as soon as it is touched by the Spirit of the Lord, we shall be enabled to see a new world of things as it were, mysteries will be opened up, and we will perceive naturally as if they were written, and in this way we shall be able to learn very rapidly indeed. If we want a knowledge of this world or of ourselves, when our spirits were born, or if we desire to know things that took place before the foundations of the world were laid or the nucleus was formed, when the sons of God shouted for joy, if we desired to know these things it would only be necessary for the Spirit of the Lord to touch the vision of our minds and light up our understanding, and we could gaze upon things past for thousands of generations of worlds before the earth was made, and we could see the succession of worlds that have been and were in existence long before this earth was formed; we could see the ordeals through which they had passed, see them brought into existence and passing through their several changes and finally become glorified celestial mansions in the presence of God. By this same Spirit . . . we could look forward into the distant future and behold new worlds formed and redeemed, and not only this, but see and understand the laws by which they were made, and the object and end of all these creations, being touched by the finger of the Almighty and lighted up by the Holy Ghost." (Orson Pratt, JD 19:178.)