There is a system by which men learn the mysteries of heaven and are saved.  That system is set out in Alma 12: 29-30: 

 

-First, angels are sent to prepare men/women.

-Second, they are allowed to behold the Lord’s glory.

-Then they converse with the Lord, at which point they are taught the things which have been prepared from the foundation of the earth for their salvation.
-All of which is driven by the man/woman’s faith, repentance and holy works.

This is in keeping with Joseph Smith’s revelation about those chosen to become a member of the Church of the Firstborn.  They are chosen by the holy angels to whom the keys of this power belong.  (D&C 77: 11.)

 

If this isn’t happening, then faith does not exist on the earth any longer.  (Moroni 7: 37.)

 

Ministering angels are an indispensable part of the Gospel of Jesus Christ.  That is why those keys were restored so early on in this dispensation, and are so widely disseminated into the Church membership. (See D&C 13 and D&C 107: 20.)