The Three-fold mission of the Church is a phrase used to denote the all-encompassing activities of The Church of Jesus Christ of Latter-day Saints. The phrase is most common in the missionary discussions--shared with non-members and inactive members of the Church, used to teach the Church's basic beliefs--but is also common terminology used in Sunday School and other meetings.
The three-fold mission of the church is to perfect the saints, proclaim the gospel, and redeem the dead. Hence, the three-fold mission of the church begins with self (Alma 60:23) and works outward toward others and finally to deceased ancestors.
Perfect the Saints
An integral part of the Church's work is to help its members attain salvation through "coming unto Christ." The various meetings of the Church including Sabbath services and others, such as General Conference, are aimed at teaching gospel doctrine (or the plan of salvation).
Members of the Church are known for aiding one another in this respect through what is known as the Visiting Teaching and Home Teaching programs, in which members visit one another and share lessons as well as offer needed assistance.
Proclaim the Gospel
Members of the Church are also known for their missionary zeal. Many Latter-day Saints volunteer 18 months to two years, without pay, to their Church to share the gospel of Jesus Christ in foreign lands or other areas away from home. It is also common for members to share their beliefs with friends.
Redeem the Dead
The Church of Jesus Christ of Latter-day Saints also constructs many Mormon temples and practices in them holy ordinances as in ancient times. However, ordinances and practices relating to the Law of Moses are no longer practiced, as the Law of Moses was fulfilled by Christ.
The doctrine of the Church is that at death the physical body is discarded, and the spirit moves on to a place called the Spirit World. Spirits in the Spirit World have the same personality characteristics, desires, and freedom of choice as embodied, mortal beings. In the Spirit World, all have the opportunity to accept or reject the Savior Jesus Christ, and to accept or reject ordinances, such as baptism, that might be performed for them vicariously on earth. These ordinances are performed in Mormon temples and include Baptism for the Dead, the Temple endowment, and eternal marriage.ru:Три миссии Церкви