The “doctrine of Christ” is the plan and system whereby the children of God “fulfill all righteousness” through taking upon themselves the name of Christ in baptism, receiving and obeying the principles and ordinances of the gospel, and then enduring to the end in faith. Paul stated it as “One Lord, one faith, one baptism” (Ephesians 4:1, ) while apostate Christianity would have it as “Many Lords, many faiths, and many (or no) baptisms.” Yet there cannot be contradictory truths. It is a strait and narrow path that leads to the presence of God. There is but one plan of salvation, one priesthood, and one church. The Lord commanded that we “be one,” saying, “If ye are not one ye are not mine” (D&C 38:27).
In his great intercessory prayer, Christ implored the Father to aid all who embrace the gospel in becoming one. “I in them,” he prayed, “ and thou in me, that they may be made perfect in one.” (John 17:21-22.) Without such unity there is no perfection, nor can there be salvation. Thus the most perfect of all teaching devices is the announcement that the Father, the Son, and the Holy Ghost- three separate and distinct personages- constitute the Godhead and are “one God,” for in all things their unity is perfect.