23 Now this Moses plainly taught to the children of Israel in the wilderness, and sought diligently to sanctify his people that they might behold the face of God;
24 But they hardened their hearts and could not endure his presence; therefore, the Lord in his wrath, for his anger was kindled against them, swore that they should not enter into his rest while in the wilderness, which rest is the fulness of his glory. – (D&C 84:23–24)
33 But God did call on men, in the name of his Son, (this being the plan of redemption which was laid) saying: If ye will repent, and harden not your hearts, then will I have mercy upon you, through mine Only Begotten Son;
34 Therefore, whosoever repenteth, and hardeneth not his heart, he shall have claim on mercy through mine Only Begotten Son, unto a remission of his sins; and these shall enter into my rest.
35 And whosoever will harden his heart and will do iniquity, behold, I swear in my wrath that he shall not enter into my rest.
36 And now, my brethren, behold I say unto you, that if ye will harden your hearts ye shall not enter into the rest of the Lord; therefore your iniquity provoketh him that he sendeth down his wrath upon you as in the first provocation, yea, according to his word in the last provocation as well as the first, to the everlasting destruction of your souls; therefore, according to his word, unto the last death, as well as the first.
37 And now, my brethren, seeing we know these things, and they are true, let us repent, and harden not our hearts, that we provoke not the Lord our God to pull down his wrath upon us in these his second commandments which he has given unto us; but let us enter into the rest of God, which is prepared according to his word. – (Alma 12:33–37)
19 And no unclean thing can enter into his kingdom; therefore nothing entereth into his rest save it be those who have washed their garments in my blood, because of their faith, and the repentance of all their sins, and their faithfulness unto the end. – (3 Nephi 27:19)

The doctrine on resting has been wrested: Enter into the Rest of the Lord

The Book of Mormon prophet Alma taught that priesthood ordinances were designed to prepare mankind to come unto Christ. He declared:
“Now these ordinances were given after this manner, that thereby the people might look forward on the Son of God, it being a type of his order, or it being his order, and this that they might look forward to him for a remission of their sins, that they might enter into the rest of the Lord” (Alma 13:16).
He also taught that during premortality, God tested and selected the men who would be His priesthood leaders in this life. They were “called and prepared from the foundation of the world according to the foreknowledge of God, on account of their exceeding faith and good works … to teach his commandments unto the children of men, that they also might enter into his rest” (Alma 13:3, 6).
The Prophet Joseph Smith added, “Every man who has a calling to minister to the inhabitants of the world was ordained to that very purpose in the Grand Council of heaven before this world was.”
Thus, a primary responsibility of all who hold the Melchizedek Priesthood is to teach the doctrines of salvation. To prepare us to enter into the rest of the Lord so that we might “rest with him in heaven” (Moroni 7:3) is what the ordinances of the Melchizedek Priesthood are all about.
Heavenly Father loves each of His children and wants all of us to return to Him. He has provided prophets and priesthood leaders with true priesthood authority to help us stay on the strait and narrow path. We have, then, the guidance of these leaders to help us enter into His rest.
Elder Bruce R. McConkie (1915–1985) taught: “The rest of the Lord, where mortals are concerned, is to gain a perfect knowledge of the divinity of the great latter-day work. [President Joseph F. Smith said,] ‘It means entering into the knowledge and love of God, having faith in his purpose and in his plan, to such an extent that we know we are right, and that we are not hunting for something else; we are not disturbed by every wind of doctrine, or by the cunning and craftiness of men who lie in wait to deceive.’ It is ‘rest from the religious turmoil of the world; from the cry that is going forth, here and there—lo, here is Christ; lo, there is Christ.’ … The rest of the Lord, in eternity, is to inherit eternal life, to gain the fulness of the Lord’s glory.”
From this we understand that in this life “the rest of the Lord” comes as we increase our knowledge of, and faith in, the reality of Jesus Christ, even to the assurance that He lives and loves us. “The rest of the Lord” in eternity is entering into the presence of the Lord.1

Rest assured, “When our leaders speak, the thinking has been done!”2  

  1. Enter into the Rest of the Lord, By Elder W. Craig Zwick, 2012
  2. When our leaders speak, the thinking has been done, By Common Consent