Moroni says that the gifts of God come from Christ, by the power of the Holy Ghost and by the Spirit of Christ. (Moro. 10.) In other words, the gifts come by the power of that Spirit who is the Holy Ghost, but the Spirit of Christ (or light of Christ) is the agency through which the Holy Ghost operates.
Their purpose is to enlighten, encourage, and edify the faithful so that they will inherit peace in this life and be guided toward eternal life in the world to come. Their presence is proof of the divinity of the Lord’s work; where they are not found, there the Church and kingdom of God is not. The promise is that they shall never be done away as long as the earth continues in its present state, except for unbelief (Moro. 10:19), but when the perfect day comes and the saints obtain exaltation, there will be no more need for them. As Paul expressed it, ‘When that which is perfect is come, then that which is in part shall be done away.’ (1 Cor. 13.)
Faithful persons are expected to seek the gifts of the Spirit with all their hearts. They are to ‘covet earnestly the best gifts’ (1 Cor. 12:31; D. & C. 46:8), to ‘desire spiritual gifts’ (1 Cor. 14:1), ‘to ask of God, who giveth liberally.’ (D. & C. 46:7; Matt. 7:7–8.) To some will be given one gift; to others, another; and ‘unto some it may be given to have all those gifts, that there may be a head, in order that every member may be profited thereby.’ (D. & C. 46:29.)
(Bruce R. McConkie, Mormon Doctrine, p. 314)