Revelation 17:1-2 The whore that sitteth upon many waters

Bruce R. McConkie:
"In other words, the church of the devil is the world; it is all the carnality and evil to which fallen man is heir; it is every unholy and wicked practice; it is every false religion, every supposed system of salvation which does not actually save and exalt man in the highest heaven of the celestial world. It is every church except the true church, whether parading under a Christian or a pagan banner. As Moroni will say in a later era of Nephite history, and as we shall ascertain in our evaluation of Rev. 18:1-24, it is "secret combinations," oath-bound societies, and the great world force of Godless communism. (Ether 8:14-26)."
"And in these last days it is spread upon all the earth -- the Americas, Europe, Asia, India, the islands of the seas. It is the combined forces of the ungodly. It is Babylon the great which shall fall. "I beheld the church of the Lamb of God, and its numbers were few," Nephi says of our day, "because of the wickedness and abominations of the whore who sat upon many waters; nevertheless, I beheld that the church of the Lamb, who were the saints of God, were also upon all the face of the earth; and their dominions upon the face of the earth were small, because of the wickedness of the great whore whom I saw." (1 Ne. 14:12)."
"In Rev. 12:1 the woman (a faithful wife living in lawful wedlock) is "the church of God"; here the great whore (an unfaithful woman living the life of a harlot, in lust and 1696 debauchery) is the church of the devil. "Behold there are save two churches only," the angel said to Nephi, "the one is the church of the Lamb of God, and the other is the church of the devil; wherefore, whoso belongeth not to the church of the Lamb of God belongeth to that great church, which is the mother of abominations; and she is the whore of all the earth. And it came to pass that I looked and beheld the whore of all the earth, and she sat upon many waters; and she had dominion over all the earth, among all nations, kindreds, tongues, and people." (1 Ne. 14:10-11)" (DNTC, pgs 1695-6).

Revelation 7:3 Sealed in their Foreheads

Bruce R. McConkie:
"Sealed the servants of our God in their foreheads] Of this sealing the Prophet Joseph Smith said: "Four destroying angels holding power over the four quarters of the earth until the servants of God are sealed in their foreheads, which signifies sealing the blessing upon their heads, meaning the everlasting covenant, thereby making their calling and election sure. When a seal is put upon the father and mother, it secures their posterity, so that they cannot be lost, but will be saved by virtue of the covenant of their father and mother" (Teachings, p. 321). Thus, if both parents and children have their calling and election made sure, none so involved shall be lost; all shall come forth to an inheritance of glory and exaltation in the kingdom of God" (DNTC, p 1646).

Revelation 4:8 The Four Beasts

Joseph Smith:
“Says one, ‘I cannot believe in the salvation of beasts.’ Any man who would tell you this could not be, would tell you that the revelations are not true. John heard the words of the beast giving glory to God, and understood them. God who made the beasts could understand every language spoken by them. The beasts were four of the most noble animals that filled the measure of their creation, and had been saved from other worlds, because they were perfect. They were like angels in their sphere. We are not told where they came from, and I do not know; but they were seen and heard by John praising and glorifying God.” (DHC, vol. 5, pp. 343–44.)

1 Peter 3:19 Spirit Prison

President Joseph Fielding Smith taught the following concerning the work of salvation for the dead:

“All those who did not have an opportunity here to receive it, who there repent and receive the gospel, shall be heirs of the celestial kingdom of God. The Savior inaugurated this great work when he went and preached to the spirits held in prison, that they might be judged according to men in the flesh (or in other words, according to the principles of the gospel) and then live according to God in the spirit, through their repentance and acceptance of the mission of Jesus Christ who died for them” (Doctrines of Salvation, comp. Bruce R. McConkie, 3 vols. [1954–56], 2:132–33).

Regarding the preaching of the gospel in the spirit world, President Lorenzo Snow taught:

“When the Gospel is preached to the spirits in prison, the success attending that preaching will be far greater than that attending the preaching of our Elders in this life. I believe there will be very few indeed of those spirits who will not gladly receive the Gospel when it is carried to them. The circumstances there will be a thousand times more favorable” (“Discourse by President Lorenzo Snow,” Millennial Star, Jan. 22, 1894, 50).

1 Peter 3:15 Be ready to give an answer to every man that asketh

President Thomas S. Monson:

“We will have opportunities throughout our lives to share our beliefs, although we don’t always know when we will be called upon to do so. Such an opportunity came to me in 1957, when I worked in the publishing business and was asked to go to Dallas, Texas, [USA,] sometimes called ‘the city of churches,’ to address a business convention. Following the conclusion of the convention, I took a sightseeing bus ride through the city’s suburbs. As we passed the various churches, our driver would comment, ‘On the left you see the Methodist church’ or ‘There on the right is the Catholic cathedral.’

“As we passed a beautiful red brick building situated upon a hill, the driver exclaimed, ‘That building is where the Mormons meet.’ A lady in the rear of the bus called out, ‘Driver, can you tell us something more about the Mormons?’

“The driver pulled the bus over to the side of the road, turned around in his seat, and replied, ‘Lady, all I know about the Mormons is that they meet in that red brick building. Is there anyone on this bus who knows anything more about the Mormons?’”

“I waited for someone to respond. I gazed at the expression on each person’s face for some sign of recognition, some desire to comment. Nothing. I realized it was up to me to do as the Apostle Peter suggested, to ‘be ready always to give an answer to every man that asketh you a reason of the hope that is in you.’ I also realized the truth of the adage ‘When the time for decision arrives, the time for preparation is past.’

“For the next 15 or so minutes, I had the privilege of sharing with those on the bus my testimony concerning the Church and our beliefs. I was grateful for my testimony and grateful that I was prepared to share it” (“Dare to Stand Alone,” 67).