Latter-day Saints believe that eons ago, God, in his infinite wisdom and never-ending mercy, formulated a plan whereby his children could experience a physical existence, including mortality, and then return to live in his presence in eternal felicity and glory. This plan, alternately called "the Plan of Salvation" (Jarom 1:2; Alma 42:5; Moses 6:62), "the plan of redemption" (Jacob 6:8; Alma 12:25;42:11), and the "great plan of happiness" (Alma 42:8), provided both the way and the means for everyone to receive salvation and gain eternal life. Eternal life is God's greatest gift to his children (D&C 6:13), and the Plan of Salvation is his way of making it available to them.
Although the term "Plan of Salvation" is used repeatedly in latter-day scripture, it does not occur in the Bible, though the doctrines pertaining to it are discoverable in its pages.
The Father is the author of the Plan of Salvation; Jesus Christ is its chief advocate; the Holy Spirit helps carry it out, communicating God's will to men and helping them live properly.
13 If thou wilt do good, yea, and hold out faithful to the end, thou shalt be saved in the kingdom of God, which is the greatest of all the gifts of God; for there is no gift greater than the gift of salvation.
Doctrine and Covenants 6:13