Acts 26

As Paul stood before King Agrippa, he recounts his experience on the road to Damascus. In this visitation, the Savior said to Paul -

"...rise, and stand upon thy feet: for I have appeared unto thee for this purpose, to make thee a minister and a witness both of these things which thou hast seen, and of those things in the which I will appear unto thee;
17 Delivering thee from the people, and from the Gentiles, unto whom now I send thee,
18 To open their eyes, and to turn them from darkness to light, and from the power of Satan unto God, that they may receive forgiveness of sins, and inheritance among them which are sanctified by faith that is in me." (New Testament Acts 26:16 - 18)

In His own words, the Savior tells Paul that not only will he be a witness of this event that he has seen but that he will be a witness of additional revelations that will come to him. The Prophet Joseph Smith penned of true saints -

"We believe all that God has revealed, all that He does now reveal, and we believe that He will yet reveal many great and important things pertaining to the Kingdom of God." (Pearl of Great Price Articles of Faith 1:9)

Such revelation for the purpose to -

To open their eyes, and to turn them from darkness to light, and from the power of Satan unto God, that they may receive forgiveness of sins, and inheritance among them which are sanctified by faith that is in me...that they should repent and turn to God, and do works meet for repentance." (New Testament Acts 26:18 - 20)

Paul taught that -

"...man is justified by faith..." (New Testament Romans 3:28)

Now he teaches we are "sanctified by faith". Sanctify meaning to be made clean, pure, and holy. This seems to make sense as we ponder -

"That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.
10 For with the heart man believeth unto righteousness..." (New Testament Romans 10:9 - 10)

That is unto cleanliness and holiness. Elder Bruce R. McConkie said -

"Those who go to the celestial kingdom of heaven have to be sanctified, meaning that they become clean and pure and spotless. They've had evil and sin and iniquity burned out of their souls as though by fire, and the figurative expression there is "the baptism of fire." Here again it is a process. Nobody is sanctified in an instant, suddenly. But if we keep the commandments and press forward with steadfastness after baptism then degree by degree and step by step we sanctify our souls until that glorious day when we're qualified to go where God and angels are." ("Jesus Christ and Him Crucified," Brigham Young University Speeches of the Year, 1976, p. 399) TLDP:605

Paul explains to King Agrippa what is "faith that is in me" -

"...that they should repent and turn to God, and do works meet for repentance." (New Testament Acts 26:20)

Alma taught of those -

"...choosing to repent and work righteousness rather than to perish; Therefore they were...sanctified, and their garments were washed white through the blood of the Lamb.
12 Now they, after being sanctified by the Holy Ghost, having their garments made white, being pure and spotless before God, could not look upon sin save it were with abhorrence..." (Book of Mormon Alma 13:10 - 12)

Moroni's final words were in regards to the sanctification by faith -

"...come unto Christ, and be perfected in him, and deny yourselves of all ungodliness; and if ye shall deny yourselves of all ungodliness, and love God with all your might, mind and strength, then is his grace sufficient for you, that by his grace ye may be perfect in Christ; and if by the grace of God ye are perfect in Christ, ye can in nowise deny the power of God.
33 And again, if ye by the grace of God are perfect in Christ, and deny not his power, then are ye sanctified in Christ by the grace of God, through the shedding of the blood of Christ, which is in the covenant of the Father unto the remission of your sins, that ye become holy, without spot." (Book of Mormon Moroni 10:32 - 33)