On 1 Cor 15:29:
The Apostle Paul did not urge his hearers to practice the principle, nor did he command it. He merely used the case as an illustration. Paul did not worship the “unknown God” of the pagans because he used the argument to tell his gospel story when he found an altar to the pagan unknown god (Acts 17:23). At times even Christ projected himself not a false position for argument’s sake: “If I by Beelzebub cast out devils, by whom do your children cast them out?” (Matthew 12:27 or Like 11:19.) There is no mention of baptism for the dead in the Bible up until Paul—and no mention afterward. Paul, as well as the other apostles, rather than endorsing baptism for the dead as then practiced, seems to have exercised a counteracting influence upon this ordinance, for it was perpetuated only among heretics in his day. (Charles R. Hield and Russell F. Ralston, Baptism for the Dead [rev ed.; Independence, Miss.: Herald Publishing House, 1953], 32-33)
Mal 4:6 (Moroni’s quotation thereof):
Moroni’s quoting of this Scripture puts the passage in a much different and clearer light. The children shall again be made aware of the promises made to their righteous forebears. The children here referred to are the Jews and the children of Israel. The fathers are the ancient prophets. Thus this passage as quoted by Moroni, means that there shall be planted again in the hearts (mind, the attention) of the children (the Jews and the lost sheep of the house of Israel who have departed from the ways of the Lord) the promises (prophecies and covenants of God) made to their fathers (God’s prophets and the early leaders of the house of Israel). This being true, the children (Israel) will turn their hearts again (their lives) to the fathers (God’s prophets and their teaching) and accepting anew their spiritual leadership and divine message, will be saved the destruction that comes to those who reject the teachings and laws of God. All Latter Day Saints look forward to the time when the Jews will again follow the teachings of their ancient prophets, and accept Christ as their Messiah. (Charles R. Hield and Russell F. Ralston, Baptism for the Dead [rev ed.; Independence, Miss.: Herald Publishing House, 1953], 33-34)
On D&C 127 and 128:
These two letters were put in the 1844 edition without Conference authority, not having been submitted at that time to the church for vote, either for acceptance or rejection. They should be read with this in mind, being careful not to reject the good, and such truth as does not contradict the “written word” of God. The Reorganized Church in 1878 by General Conference Resolution, Number 215, recognized “the revelations of God contained in the Book of Doctrine and Covenants . . . which have been . . . accepted by the church.” (Charles R. Hield and Russell F. Ralston, Baptism for the Dead [rev ed.; Independence, Miss.: Herald Publishing House, 1953], 40)
JST Hebrews 11:40:
The fact that God caused Joseph Smith by inspiration to correct the Scripture misquoted in the King James Version, certainly shows that the writer of the letter (Reorganized Doctrine and Covenants, Section 110; Utah Doctrine and Covenants 128:15) disregarded the previous inspiration received, for in this letter he quotes an uninspired and incorrect Scripture to support the theory advanced adding to it a conclusion that could not be arrived at if he had used the inspired correction of that Scripture. (Charles R. Hield and Russell F. Ralston, Baptism for the Dead [rev ed.; Independence, Miss.: Herald Publishing House, 1953], 41)
No mention of baptism for the dead was placed in the “Articles of Faith” (Epitome of Faith) prepared by Joseph Smith for Mr. John Wentworth, editor of the Chicago Democrat. These statements of belief were published by Joseph Smith in the Times and Seasons, Volume 3, Number 9, pages 706-710, March 1, 1842 (after the revelation mentioning baptism for the dead). The ordinances that are essential to salvation are listed, but not baptism for the dead. This would indicate that Joseph Smith did not consider it essential for salvation. (Charles R. Hield and Russell F. Ralston, Baptism for the Dead [rev ed.; Independence, Miss.: Herald Publishing House, 1953], 42)