The following quotes come from the book The Teachings of Harold B. Lee, who was the eleventh president of the LDS Church. The original edition was 1996 by Bookcraft and was republished by Intellectual Reserve in 2015.  This was an employee gift by the First Presidency in 2015. To visit the site with all of the books and quotes from these, go here.

Angels

“THOSE IN THE SPIRIT WORLD MAY BE GUARDIAN ANGELS TO THOSE IN MORTALITY. Who are guardian angels? Well, it would appear that someone who is quickened by some influence, not yet celestialized, is permitted to come back as a messenger for the purpose of working with and trying to aid those who are left behind” (Harold B. Lee, Funeral Service for Margaret Peel Childs, May 3, 1958. Cited in The Teachings of Harold B. Lee, p. 60).

Apostasy

“PEOPLE APOSTATIZE DUE TO IGNORANCE OR SIN. In nine cases out of ten—I’d say in every case—those who apostatize from this church do it from one of two reasons, either because of their ignorance of the doctrine or because of their sinfulness and falling away from the truth” (Harold B. Lee, remarks made in Paris, France, March 29, 1960. Cited in The Teachings of Harold B. Lee, p. 390).

“Today the greatest enemies we have are those who, for flattery of the world, would betray the Savior by denying His prophets and making light of Church pronouncements on vital issues that strike at the very foundation of the Lord’s work. Such we have among us today—make no mistake” (Harold B. Lee, “Yet are the Salt of the Earth,” Delta Phi Conference Address, Assembly Hall on Temple Square, March 5, 1966. Cited in The Teachings of Harold B. Lee, p. 392).

Book of Mormon Geography

“DON’T BE CONCERNED OVER BOOK OF MORMON GEOGRAPHY. Some say the Hill Cumorah was in southern Mexico (and someone pushed it down still farther) and not in western New York. Well, if the Lord wanted us to know where it was or where Zarahemla was, He’d have given us latitude and longitude, don’t you think? And why bother our heads trying to discover with archaeological certainty the geographical locations of the cities of the Book of Mormon like Zarahemla?” (Harold B. Lee, “Loyalty,” address to Seminary and Institute Faculty, Brigham Young University, July 8, 1966. Cited in The Teachings of Harold B. Lee, p. 156).

Church

“THE CHURCH IS NOT OUTDATED. When you hear some of our young scholars, so styled, who read by the lamp of their own conceit and think that the Church is outmoded and we are still believing in these ‘first-century myths,’ as they speak of them in derision, you must keep in mind . . . that the Church is not out-of-date and ever will be ahead of anything that science has yet given us or may yet give us” (Harold B. Lee, “Story of the Creation,” BYU Summer School lecture, June 22, 1954. Cited in The Teachings of Harold B. Lee, p. 389. Ellipsis in original).

General Conference

“We have the adult magazine we call the Ensign. Here you have the voice of the church. No doubt you will find the messages of this conference appearing in the Ensign magazine. You will have excerpts that are intended for the children and the youth in other magazines. If you don’t avail yourself of the opportunity of having them in your homes, you will be failing to have the finest communications that we can bring to you at the present time” (Harold B. Lee, British Area Conference Report, August 29, 1971. Cited in The Teachings of Harold B. Lee, p. 558).

God

“I think our chief difficulty in discussing this subject [the progression of God] grows out of the fact that God is progressing in power, in dominion, in glory, and that progression is going on constantly and will never cease” (Harold B. Lee, “Relationship God to Man,” BYU Summer School Lecture, June 18, 1954. Cited in The Teachings of Harold B. Lee, p. 3. Brackets in original).

Incarnation, of Jesus

“TEACHERS SHOULD NOT SPECULATE ON THE MANNER OF CHRIST’S BIRTH. We are very much concerned that some of our Church teachers seem to be obsessed of the idea of teaching doctrine which cannot be substantiated and making comments beyond what the Lord has actually said. You asked about . . . the birth of the Savior. Never have I talked about sexual intercourse between Deity and the mother of the Savior” (Harold B. Lee, The Teachings of Harold B. Lee, pp. 13-14. Ellipsis in original).

Joseph Smith

“A TESTIMONY OF JOSEPH SMITH IS VITAL. No man can accept Jesus Christ as the Savior of the world, no man can accept this as His church, the Church of Jesus Christ, unless he can accept Joseph Smith as God’s mouthpiece and the restorer of His work in these latter days” (Harold B. Lee, “Two Great Commemorations,” Christmas message given to the Church Office employees, December 14, 1972. Cited in The Teachings of Harold B. Lee, p. 371).

“I believe with all my soul that Satan in very person was there at the Hill Cumorah when Joseph went to get the plates. He was there when Joseph prayed in the grove. He was there on other occasions trying with all his power to destroy the appointment of God’s modern prophet as he had tried to tempt the Master” (Harold B. Lee, “He Lived Great, Died Great in Eyes of God and His People,” 13^th Annual Joseph Smith Memorial, 4 December 1955. Cited in The Teachings of Harold B. Lee, p. 373).

Leaders

“CRITICISM OF LEADERS INVITES SATAN’S INFLUENCE. Now, Latter-day Saints, the devil knows your weak points, and just the moment you lower your guard he is going to move in. And one of the first signs of spiritual sickness is when criticism against the leaders who preside over you begins to come. That is the first evidence of spiritual illness. Beware; keep up your guard, by keeping the commandments, and keeping active in this church” (Harold B. Lee,” Millennial Star 122 (May 1960), p. 201. Cited in The Teachings of Harold B. Lee, p. 41).

Marriage

“We have always said, in effect, that if you plan a marriage to someone outside the Church, you had better count the cost. When the children come along there will come a contest, and if it results in a quarrel, they might say, ‘Just let them grow up and make their own choice.’ In that case you let children grow up with no choice. The fact is that they will be wholly irreligious. So we try to say, ‘It will be wise for . . . Mormons to marry Mormons.’ Therein is the safest course” (Harold B. Lee, “First Businessman Leader of Mormons to Rely on Revelation,” Los Angeles Times, August 21, 1972. Cited in The Teachings of Harold B. Lee, p. 234. Ellipsis in original).

“Some of you may decide to marry out of the Church with the secret hope of converting your companion to your religious views. Your chances for happiness in your married life are far greater if you make that conversion before marriage” (Harold B. Lee, “Unwelcome Wedding Guests,” Radio Address delivered April 8, 1945. Cited in The Teachings of Harold B. Lee, p. 235).

“THE PRIME PURPOSE OF MARRIAGE IS TO PROVIDE MORTAL BODIES FOR GOD’S SPIRIT CHILDREN. You young men must ever keep in mind that your lovely companion is possessed of finer sensibilities than you, and if your private conduct is brutal or beastly, bitterness and even disgust may drive out of her heart the affection and regard she once held for you. Both of you must remember that the prime purpose of your marriage under God’s command is to build the bridge from the eternity of spirits to mortality, over which God’s spirit children might come into mortal bodies. Your failure to remember that revealed truth will be your failure to attain the highest bliss in married life” (Harold B. Lee, “Toward Happy Homes.” Radio Address delivered May 13, 1945. Cited in The Teachings of Harold B. Lee, p. 238).

“TEMPLE MARRIAGE MUST BE PERFORMED IN MORTALITY. Marriage is not performed in the heavens hereafter. If you would be united for eternity as husband and wife and family, that sealing must be performed here upon this earth by the authority of the holy priesthood. Knowing and believing this, no one of you should be content until you have prepared yourself to enter into this eternal relationship” (Harold B. Lee, “Unwelcome Wedding Guests,” Radio Address delivered April 8, 1945. Cited in The Teachings of Harold B. Lee, p. 243).

“SATAN DOES NOT WANT US TO MARRY IN THE TEMPLE. The devil knows if he can get a girl to marry out of the Church or to marry one who is not a member of the Church or outside the temple, he knows that after this life there will be no increase and he has won a great victory” (Harold B. Lee, “By the Power of the Holy Ghost You May Know the Truth of All Things,” Devotional for Young Adults, San Diego, CA, November 3, 1972. Cited in The Teachings of Harold B. Lee, p. 244).

Obedience

“The simple essence of all you need to know about the Atonement is to be found in the teachings of the great prophet Nephi when he said, ‘We labor diligently to write, to persuade our children, and also our brethren, to believe in Christ, and to be reconciled to God; for we know that it is by grace that we are saved, after all we can do’ (2 Nephi 25:23). Don’t you let anyone try to persuade you to any other doctrine than that. Except for the atoning power, the redeeming power, of the Master, redeeming the world from the Fall, bringing us back into relationship with one of the Godhead, the Holy Ghost—were it not for His sacrifice for us, none of us would be worthy to enter in His presence, except we were bathed in His blood through repentance of all our sins and our faithfulness to the end (see 3 Nephi 27:19). That [is] the pure doctrine of the scriptures” (Harold  B. Lee, “Viewpoint of a Giant,” Summer School Devotional Address, Department of Seminaries and Institutes of Religion, Brigham Young University, July 18, 1968. Cited in The Teachings of Harold B. Lee, pp. 7-8).

“ULTIMATE SALVATION COMES TO THOSE WHO OBEY. The ancient prophets of this western continent have clearly set forth in understandable language the obligation of each individual to obtain the highest of these eternal privileges in mortality and in the world to come, for here we find written: ‘For we labor diligently to write, to persuade our children, and also our brethren, to believe in Christ . . . for we know that it is by grace that we are saved, after all we can do’ (2 Nephi 25:23). In other words, each must do all he can to save himself from sin; then he may lay claim to the blessings of redemption by the Holy One of Israel, that all mankind may be saved by obedience to the law and ordinances of the gospel. Jesus also atoned not only for Adam’s transgressions but for the sins of all mankind. But redemption from individual sins depends upon individual effort, with each being judged according to his or her works. The scriptures make it clear that while a resurrection will come to all, only those who obey the Christ will receive the expanded blessing of eternal salvation” (Harold B. Lee, “To Ease the Aching Heart,” Ensign, April 1973, p. 5. Cited in The Teachings of Harold B. Lee, pp. 17-18. Ellipsis in original).

“THERE IS SAFETY IN KEEPING THE COMMANDMENTS. The greatest message that one in this position could give to the membership of the Church is to keep the commandments of God, for therein lies the safety of the Church and the safety of the individual. Keep the commandments. There could be nothing that I could say that would be a more powerful or important message today” (Harold B. Lee, Ensign back cover, August 1972. Cited in The Teachings of Harold B. Lee, p. 85).

“THE LORD BLESSES US TO THE DEGREE WE KEEP THE COMMANDMENTS. The Lord will bless us to the degree to which we keep His commandments. Nephi put this principle in a tremendous orbit when he said, ‘For we labor diligently to write, to persuade our children, and also our brethren, to believe in Christ, and to be reconciled to God; for we know that it is by grace that we are saved, after all we can do’ (2 Nephi 25:23). The Savior’s blood, His atonement, will save us, but only after we have done all we can to save ourselves by keeping His commandments” (Harold B. Lee, Address at MIA Conference, 17 June 1966. Cited in The Teachings of Harold B. Lee, p. 186).

Preexistence

“The fact that you and I are here on this earth with a physical body is an evidence that we were among those who kept our first estate. If we hadn’t passed the test we wouldn’t be here; we would be down with Satan trying to tempt the ones who had a body” (Harold B. Lee, ‘Who Am I?” Grant Stake Senior Aaronic School, February 18, 1957. Cited in The Teachings of Harold B. Lee, p. 32).

“LUCIFER AND HIS HOSTS WERE BANISHED DUE TO THEIR REBELLION. The penalty for opposition to [the plan of salvation] was the banishment and the loss of the privilege of mortal life by one-third of the spirits in heaven, marshaled and led in their opposition by Lucifer, an illustrious son in the morning of God’s creations. Satan’s hosts, now cast out for rebellion, are ever ready to attack mortal beings and to destroy them in mortality by enticing them to commit sins which would unfit them for their eternal glory” (Harold B. Lee, “The Sixth Commandment” in The Ten Commandments Today: A Discussion of the Decalog, p. 88. Cited in The Teachings of Harold B. Lee, p. 33).

Priesthood

“NEVER TAKE THE PRIESTHOOD INTO UNHOLY PLACES. Brethren, in your hands is given a sacred trust not only to have the authority to act in the name of the Lord, but to so prepare yourselves as clean and pure vessels so that the power of Almighty God may be manifested through you as you officiate in the sacred ordinances of the priesthood. Never take your priesthood into places where you would be ashamed to have the President of the Church see you” (Harold B. Lee, European Area Conference Report, August 25, 1973. Cited in The Teachings of Harold B. Lee, p. 502).

Repentance

“DEATHBED REPENTANCE IS BETTER THAN NONE. I have never placed great stock in deathbed repentance, but I have often said it is better than no repentance at all” (Harold B. Lee, Funeral Services for Carol Anniett Clayton, Salt Lake City, February 1963. Cited in The Teachings of Harold B. Lee, p. 114).

“REPENTANCE MEANS TO TURN FROM SIN. Repentance, in one sentence, means turning from the things that have been wrong and never returning back to them. It isn’t to say, ‘I’m sorry,’ and then go back and do it and again say, ‘I’m sorry.’ That’s not it—it is to go about our way and sin no more. But if they sin again it is as though they haven’t been forgiven in the first instance, to use the Lord’s own language (see D&C 82:7)” (Harold B. Lee, Address at Priesthood Board Meeting, March 1, 1972. Cited in The Teachings of Harold B. Lee, p. 114).

Revelation

“THE CHURCH RECEIVES REVELATION REGULARLY. Brother [John A.] Widtsoe used to tell us about a group who gathered around him between meetings at a stake conference and said, ‘Oh, Brother Widtsoe, how long has it been since the Church received a revelation?’ And Brother Widtsoe stroked his chin for a moment and said, ‘Oh, probably since last Thursday.’ Now, when he said Thursday, he was referring to the meeting that is held in an upper room of the temple—the Presidency and the Twelve. Brother Widtsoe knew, as I know and as all who attend those meetings know, that there we see in perspective the whole church brought to review. We see wisdom beyond human wisdom, decisions prompted by powers beyond ourselves” (Harold B. Lee, “Loyalty,” address to seminary and institute faculty, Brigham Young University, July 8, 1966. Cited in The Teachings of Harold B. Lee, p. 426).

Sabbath

“LET US NOT PATRONIZE BUSINESSES OPEN ON SUNDAY. If the body of the priesthood. . . would resolve here and now that neither you nor your families will hereafter patronize any business that is open on Sunday, it wouldn’t be long until they would close their businesses on Sunday. You would wield such a force and power that you would dry up the businesses that are making their Sunday opening profitable. They are only catering to the needs of the people who are demanding Sunday service” (Harold B. Lee, Conference Report, 3 October 1970, pp. 104-105. Ellipsis in original).

Spirits

“THERE MAY BE TIMES WHEN WE CAN FEEL THE NEARNESS OF DEPARTED SPIRITS. The Prophet Joseph Smith taught: ‘The spirits of the just are exalted to a greater and more glorious work; hence they are blessed in their departure to the world of spirits.’ Now listen to this: ‘Enveloped in flaming fire, they are not far from us, and know and understand our thoughts, feelings, and motions, and are often pained therewith.’ (Teachings of the Prophet Joseph Smith [Salt Lake City: Desert Book co., 1938], p. 326.) It may be that when the anxieties of the passing of this day shall have gone, in the quiet loneliness in your home, in a day not too intense because of the motherhood requirements, there will come times when you will say, ‘My, he seemed to be so close to me. I seem to have felt his nearness.’ And it will be real. It will be something you can’t deny” (Harold B. Lee, “Introduction and Overview of Priesthood Leadership Program.” Regional Representatives’ Seminar, September 27, 1967. Cited in The Teachings of Harold B. Lee, p. 60).

Temptation

“THE REBELLIOUS SPIRITS WHO WERE CAST OUT NOW TRY TO TEMPT US. The fact that you are here in this mortal existence is an evidence that you accepted our Heavenly Father’s plan and entered into covenant with Him to keep His commandments in return for which you were to be given a glorified place in His kingdom. One-third of all those in the spirit world before you came to this earth were cast out because they refused the gift of this education in the ‘University of Mortality’ on the terms provided. They are the tempters who, like yourselves, have their free agency and are endeavoring to persuade you to ‘eat, drink, and be merry, for tomorrow we die’ (2 Nephi 28:7) and thus be miserable like themselves” (Harold B. Lee, “What Price Sin?” Radio Address delivered March 4, 1945. Cited in The Teachings of Harold B. Lee, p. 44).

Word of Wisdom

“I remember a sister who came into my office from a foreign country. She was working in the bishop’s storehouse in Logan, Utah. She had gone storming in to Elder Joseph F. Merrill of the Council of the Twelve and said, ‘Why, Brother Merrill, they are distributing pork from the bishop’s storehouse up there where I have been working and it is summertime.’ Elder Merrill very wisely said, ‘Go in and talk that over with Brother Lee.’ So she came in to me and repeated her comment, since I was at that time working with the welfare program. I asked, ‘Why are you so much disturbed about that?’ ‘Why,’ she said, ‘the Lord said we should not eat pork or meat in the summertime.’ I said, ‘Oh, where did he say that? I haven’t read that.’ ‘Why, in the Word of Wisdom.’ I said, ‘Not in my Doctrine and Covenants, it doesn’t say that. Will you open the Doctrine and Covenants and read me what you have just said?’ Well, she tried to justify what she had said. I suggested that she read section 49 of the Doctrine and Covenants, and told her I was not sure what a famine was as mentioned in section 89. We should eat meat sparingly, yes, as the Lord counsels. But when we reach a hard and fast conclusion contrary to what the Lord has said, be careful” (Harold B. Lee, “Doing the Right Things for the Right Reasons. Brigham Young University Speeches of the Year, April 19, 1961, pp. 32-33. Cited in The Teachings of Harold B. Lee, p. 204).