Gospel of John
John the Apostle, whom Jesus loved, wrote one of the four gospels, gospel meaning “good news.” John's account is particularly valuable because he covered 92% of material that Matthew, Mark, and Luke omitted (Bible Dictionary, p. 683). In addition to significant events in Christ's Galilean ministry, John also covered Christ's Judean ministry. Another important difference was the audience for whom John wrote. While Matthew wrote for the Jews; Mark, for the Romans or gentiles; and Luke, for the Greeks, John wrote for members of the Church, those already converted and conversant with basic information. This allows him to enhance and enrich their knowledge with deeper doctrine and more specific details, which makes him particularly significant to Latter-day Saints. John's language is also quite different in vocabulary, phraseology and presentation of events (BD, p. 683), as he makes his case for the divinity of Christ and the Plan of Salvation. In 20:32 John testifies that Jesus is the Christ (Messiah) and the Son of God. Everything he chooses to write about supports this view as if he were arguing a court case.
Particulars
The gospel of John shows Christ in the pre-mortal existence as The Son of God and The Creator. Next John discusses His birth on earth as the Only Begotten of the Father. Then John tracks Jesus as he ministers to mankind. He emphasizes, by his selection of miracles and sermons, Christ's divinity. Just as in a court case, John provides witnesses, not only regular humans, but prophets and Christ Himself.
Some of the miracles and sermons John wrote about, which the other apostles omitted, were Christ's turning water into wine; the visit of Nicodemus; the woman at the well; the discourse on the bread of life; raising Lazarus from the dead; washing the apostles' feet; the discourse about the Holy Ghost; and the promise that John would tarry on the earth (the last understandable, of course, that the other apostles might not even know this).
John uses contrasts to make his declarations clear. He often refers to darkness and light, error and truth, evil and good, and the devil and God. Contrast has historically been a common expository device among the Jews.
Joseph Smith Translation
Joseph Smith had revealed to him words that had been lost from John's record, specifically in 1:1-34; 4:1-4; 6:44; and 13: 8-10. These simple restorations help clarify John's intent. Chapter 1, which covers a long period of time (from the pre-mortal existence until Jesus was baptized), also lost the most words so the translation is the longest. All the Joseph Smith translation reveals is clarification of the greatness and goodness of Christ. The restored words in Chapter 4 clarify the reason the Jews sought to kill Jesus—that they believed in John the Baptist but not Jesus, and they thought Jesus was baptizing more than John (which He wasn't, leaving the majority of baptizing to his disciples). Chapter 6 is clarified by revealing that those who follow Heavenly Father's will, will receive Christ, and as a result, Christ will lift them up at the last day. The LDS version of Chapter 13 explains Christ's washing Peter's feet was part of the custom of the Jews where the heads, hands, and feet must be washed to obey the whole law.
LDS Value Gospel of John
The Latter-day Saints have a special love for the book of John, akin to Christ's love for John himself. They read it frequently and quote his words, “For God so loved the world, that he gave his only begotten Son, that whosoever should believe in him should not perish, but have everlasting life” (John 3:16) as a promise to live by.
