Here are some insights from a book I recently read:
Hyrum M. Smith and Janne M. Sjodahl, Doctrine and Covenants Commentary (rev ed.; Salt Lake City: Deseret Book Company, 1978)
The meaning of “Salvation”
Salvation is the greatest gift; it includes all other gifts. All other gifts are subservient to it. Salvation means deliverance from outward dangers, victory over enemies, remission of sins through acceptance of Christ and obedience to His laws, and eternal exaltation (Compare Exodus 14:13; I. Sam. 14:45; Luke 1:77; 19:9.) “Wherefore let him that thinketh he standeth take heed lest he fall.” (1 Cor. 10:12.)
“Salvation is for man to be saved from all his enemies: for, until a man can triumph over death, he is not saved. A knowledge of the priesthood [and obedience] alone will do this” (Joseph Smith, History of the Church, Vol. V., p. 403) . . . Salvation comes through the power of God; yet, only those who “endure to the end” will be saved ([sec 20] v. 25), and generally speaking, those who feel too sure of their salvation are farthest from it. Soren Kjerkegaard has expressed this thought in the following quaint paradox: “If you fear, then fear not; but if you do not fear, then fear.” (pp. 35, 104)
On D&C 10:54 teaching there is truth in all faiths
Not to destroy * * * to build up my church] When the Lord understood to establish again His Church among the children of men, He did not intend to set aside any truth they had discovered, or in which they believed. “Mormonism” embraces all truth, no matter where found. It is a fact that the Latter-day Saints, as the late Bishop F.S. Spalding (Episcopalian), of Salt Lake City, expressed it, believed all the truth that other Christians believe, and then something more. “Mormonism” is constructive, not destructive. It recognizes truth everywhere, and it builds on such truth. Truth is its building material. (p. 57)
Ecclesiology and fallibility of Church leadership and members:
The Church is said to be the “body” of Christ (Eph. 1:23). As a “body” it may have its limitations, and even failings, for the human element in it has not reached perfection; but as long as it has the Holy Priesthood and is true to Him, keeping His commandments, observing His ordinances, and promulgating His gospel, it is His “body,” the object of His love. He is the “head,” although He is on the other side of the veil; for He rules and guides its affairs, and is as really present in the Church, as if He were among us in the flesh. The Tabernacle in the wilderness had two compartments, separated by a veil,--the Holy and the Most Holy. The Presence of God rested on the Mercy Seat in the cap, and all Israel was guided by it. The Church, too, has two grand divisions, one on this side of the veil, and one on the other side. Christ is now, in a special sense, with the Church on the other side, but His presence here is none the less real, for there is only a veil between this side and the other.
The Hebrews, anciently, had their Assembly, which was a representative and ruling body. The institution survived in the ruling body of the Synagogue, which was called the “Church” (Matt. 18:17). The Greek republics also had their representative assemblies, known as “churches” (ecclesiae). They were visible bodies, and so is the Church of Christ. IT is an assembly as tangible as any Congress or Parliament. (pp. 113-14)
On D&C 45:3-5 and the intercessory work of Jesus Christ
3. Him who is the advocate with the Father] That is another reason for obedience. Christ, our Lord, is our legal representative at the eternal bar of justice. He pleads our causes. But a client must follow the counsel of his advocate, or lose his case.
4-5. Behold the sufferings and death * * * spare these my brethren] This is the plea of the Son. In the Mosaic dispensation the priest presented before God a sacrifice slain in behalf of the Israelites. That was a type of Christ’s sacrifice, who presents Himself as the Lamb of God, slain for us, and intercedes in our behalf, on the condition that we are willing to obey Him and leave our cause in His hands. There is but one Mediator between God and man, and that is our blessed Savior. His redeemed and sanctified brethren may pray for one another, but they cannot enter behind the veil in behalf of others, or even in behalf of themselves. Our justification, our salvation, is due only to the mediation of Christ.
That thyself might be glorified] Christ died, that His Father might be glorified, and the salvation of His children in His glory. (p. 253)
On D&C 77:6 and the “seven thousand years” beginning, not at the creation of the world, but the Fall of man:
The book * * * sealed] The book which is sealed contains the history of the seven thousand years of the temporal existence of the earth.
“By the seven thousand years of temporal existence is meant the time of the earth’s duration from the fall of Adam to the end of time, which will come after the Millennium and ‘a little season’ which will follow. The earth and all on it were in a spiritual condition before the fall, for mortality had not come bringing temporal conditions. We are now living in the second period of the earth’s history, which is referred to as being a telestial condition. In other words, a condition where wickedness and all the vicissitudes of morality endure. It is the earth and its inhabitants in the fallen state which Adam brought through his transgression. This condition will continue until Christ comes.” (Ch. History and Modern Revelation, p. 64, second series.) (p. 474)