D&C 138

In the great revelation received by President Joseph F. Smith, we learn that -

"...there were gathered together in one place an innumerable company of the spirits of the just, who had been faithful in the testimony of Jesus while they lived in mortality;
13 And who had offered sacrifice in the similitude of the great sacrifice of the Son of God, and had suffered tribulation in their Redeemer's name." (Doctrine and Covenants Section 138:12 - 13)

In this company of spirits there were not a few, but "an innumerable company of the spirits of the just". This innumerable company were they that had lived in the flesh before the coming of the Savior that had been faithful in the testimony of Jesus. It becomes apparent that the blessings of exaltation are not limited to just a few. It is interesting that these saints knew that they would receive the blessings the Savior had prepared for them for -

"All these had departed the mortal life, firm in the hope of a glorious resurrection, through the grace of God the Father and his Only Begotten Son, Jesus Christ.
15 I beheld that they were filled with joy and gladness, and were rejoicing together because the day of their deliverance was at hand.
16 They were assembled awaiting the advent of the Son of God into the spirit world, to declare their redemption from the bands of death.
17 Their sleeping dust was to be restored unto its perfect frame, bone to his bone, and the sinews and the flesh upon them, the spirit and the body to be united never again to be divided, that they might receive a fulness of joy." (Doctrine and Covenants Section 138:14 - 17)

These blessings would be exaltation because they would receive "a fulness of joy". Elder Bruce R. McConkie taught -

"All the faithful Saints, all of those who have endured to the end, depart this life with the absolute guarantee of eternal life.

There is no equivocation, no doubt, no uncertainty in our minds. Those who have been true and faithful in this life will not fall by the wayside in the life to come. If they keep their covenants here and now and depart this life firm and true in the testimony of our blessed Lord, they shall come forth with an inheritance of eternal life.

We do not mean to say that those who die in the Lord, and who are true and faithful in this life, must be perfect in all things when they go into the next sphere of existence. There was only one perfect man—the Lord Jesus whose Father was God.

There have been many righteous souls who have attained relative degrees of perfection, and there have been great hosts of faithful people who have kept the faith, and lived the law, and departed this life with the full assurance of an eventual inheritance of eternal life.

There are so many things they will do and must do, even beyond the grave, to merit the fulness of the Father’s kingdom in that final glorious day when the great King shall say unto them ‘Come, ye blessed of my Father, inherit the kingdom prepared for you from the foundation of the world.’ (Matt. 25:34.)

But what we are saying is that when the saints of God chart a course of righteousness, when they gain sure testimonies of the truth and divinity of the Lord’s work, when they keep the commandments, when they overcome the world, when they put first in their lives the things of God’s kingdom: when they do all these things, and then depart this life—though they have not yet become perfect—they shall nonetheless gain eternal life in our Father’s kingdom; and eventually they shall be perfect as God their Father and Christ His Son are perfect.” (In Conference Report, Oct. 1976, pp. 158–59; or Ensign, Nov. 1976, p. 107)