The Need for an Atonement
D&C 20
17 By these things we know that there is a God in heaven, who is infinite and eternal, from everlasting to everlasting the same unchangeable God, the framer of heaven and earth, and all things which are in them;
18 And that he created man, male and female, after his own image and in his own likeness, created he them;
19 And gave unto them commandments that they should love and serve him, the only living and true God, and that he should be the only being whom they should worship.
20 But by the transgression of these holy laws man became sensual and devilish, and became fallen man.
2 Nephi 2
Alma 22
12 And it came to pass that when Aaron saw that the king would believe his words, he began from the creation of Adam, reading the scriptures unto the king--how God created man after his own image, and that God gave him commandments, and that because of transgression, man had fallen.
13 And Aaron did expound unto him the scriptures from the creation of Adam, laying the fall of man before him, and their carnal state and also the plan of redemption, which was prepared from the foundation of the world, through Christ, for all whosoever would believe on his name.
1 Nephi 10
5 And he also spake concerning the prophets, how great a number had testified of these things, concerning this Messiah, of whom he had spoken, or this Redeemer of the world.
Mormon 9
12 Behold he created Adam, and by Adam came the fall of man. And because of the fall of man came Jesus Christ, even the Father and the Son; and because of Jesus Christ came the redemption of man.
Brigham Young
A divine debt has been contracted by the children, and the Father demands recompense. He says to his children on this earth, who are in sin and transgression, it is impossible for you to pay this debt; I will send my Only Begotten Son to pay this divine debt. .... [U]nless God provides a Savior to pay this debt it can never be paid. Can all the wisdom of the world devise means by which we can be redeemed, and return to the presence of our Father and Elder Brother, and dwell with holy angels and celestial beings? No; it is beyond the power and wisdom of the inhabitants of the earth that now live, or that ever did or ever will live, to prepare or create a sacrifice that will pay this divine debt. But God provided it, and his Son has paid it, and we, each and every one, can now receive the truth and be saved in the Kingdom of God. (Discourses of Brigham Young, p.59)