Alma 13:10-12

10 Now, as I said concerning the holy order, or this high priesthood, there were many who were ordained and became high priests of God; and it was on account of their exceeding faith and repentance, and their righteousness before God, they choosing to repent and work righteousness rather than to perish;

11 Therefore they were called after this holy order, and 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; and there were many, exceedingly great many, who were made pure and entered into the rest of the Lord their God. (Alma 13:10-12)

Alma continues to discuss the high priesthood.

Many were ordained as high priests. In the Doctrine and Covenants, we have a the patriarchal order is established from Adam to Noah

“40 The order of this priesthood was confirmed to be handed down from father to son, and rightly belongs to the literal descendants of the chosen seed, to whom the promises were made.

“41 This order was instituted in the days of Adam, and came down by lineage in the following manner:

“42 From Adam to Seth, who was ordained by Adam at the age of sixty-nine years, and was blessed by him three years previous to his (Adam’s) death, and received the promise of God by his father, that his posterity should be the chosen of the Lord, and that they should be preserved unto the end of the earth;

“43 Because he (Seth) was a perfect man, and his likeness was the express likeness of his father, insomuch that he seemed to be like unto his father in all things, and could be distinguished from him only by his age.

“44 Enos was ordained at the age of one hundred and thirty-four years and four months, by the hand of Adam.

“45 God called upon Cainan in the wilderness in the fortieth year of his age; and he met Adam in journeying to the place Shedolamak. He was eighty-seven years old when he received his ordination.

“46 Mahalaleel was four hundred and ninety-six years and seven days old when he was ordained by the hand of Adam, who also blessed him.

“47 Jared was two hundred years old when he was ordained under the hand of Adam, who also blessed him.

“48 Enoch was twenty-five years old when he was ordained under the hand of Adam; and he was sixty-five and Adam blessed him.

“49 And he saw the Lord, and he walked with him, and was before his face continually; and he walked with God three hundred and sixty-five years, making him four hundred and thirty years old when he was translated.

“50 Methuselah was one hundred years old when he was ordained under the hand of Adam.

“51 Lamech was thirty-two years old when he was ordained under the hand of Seth.

“52 Noah was ten years old when he was ordained under the hand of Methuselah.

“53 Three years previous to the death of Adam, he called Seth, Enos, Cainan, Mahalaleel, Jared, Enoch, and Methuselah, who were all high priests, with the residue of his posterity who were righteous, into the valley of Adam-ondi-Ahman, and there bestowed upon them his last blessing.

“54 And the Lord appeared unto them, and they rose up and blessed Adam, and called him Michael, the prince, the archangel.

“55 And the Lord administered comfort unto Adam, and said unto him: I have set thee to be at the head; a multitude of nations shall come of thee, and thou art a prince over them forever” (D&C 107:40-55).

They received the priesthood through their faith, repentance and righteousness. They chose to repent and live righteously rather than perish.

Those called to the priesthood were sanctified. “And Moses took of the anointing oil, and of the blood which was upon the altar, and sprinkled it upon Aaron, and upon his garments, and upon his sons, and upon his sons’ garments with him; and sanctified Aaron, and his garments, and his sons, and his sons’ garments with him” (Leviticus 8:30).

“That by reason of transgression cometh the fall, which fall bringeth death, and inasmuch as ye were born into the world by water, and blood, and the spirit, which I have made, and so became of dust a living soul, even so ye must be born again into the kingdom of heaven, of water, and of the Spirit, and be cleansed by blood, even the blood of mine Only Begotten; that ye might be sanctified from all sin, and enjoy the words of eternal life in this world, and eternal life in the world to come, even immortal glory;

“For by the water ye keep the commandment; by the Spirit ye are justified, and by the blood ye are sanctified” (Moses 6:59-60).

Their garments were washed white through the blood of the lamb.

“And no unclean thing can enter into his kingdom; therefore nothing entereth into his rest save it be those who have washed their garments in my blood, because of their faith, and the repentance of all their sins, and their faithfulness unto the end.

“Now this is the commandment: Repent, all ye ends of the earth, and come unto me and be baptized in my name, that ye may be sanctified by the reception of the Holy Ghost, that ye may stand spotless before me at the last day” (3 Nephi 27:19-20).

Their garments having been made white, they were sanctified by the Holy Ghost. “And such were some of you: but ye are washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the Spirit of our God” (1 Corinthians 6:11).

“But we are bound to give thanks alway to God for you, brethren beloved of the Lord, because God hath from the beginning chosen you to salvation through sanctification of the Spirit and belief of the truth” (2 Thessalonians 2:13).

“For whoso is faithful unto the obtaining these two priesthoods of which I have spoken, and the magnifying their calling, are sanctified by the Spirit unto the renewing of their bodies” (D&C 84:33).

They stand pure and spotless before God. “O then ye unbelieving, turn ye unto the Lord; cry mightily unto the Father in the name of Jesus, that perhaps ye may be found spotless, pure, fair, and white, having been cleansed by the blood of the Lamb, at that great and last day” (Mormon 9:6).

They could not look upon sin without abhorrence. “Let love be without dissimulation [GR sincere, unfeigned, real]. Abhor that which is evil; cleave to that which is good” (Romans 12:9).

“O Lord, wilt thou redeem my soul? Wilt thou deliver me out of the hands of mine enemies? Wilt thou make me that I may shake at the appearance of sin” (2 Nephi 4:31).

“The fear of the Lord is to hate evil: pride, and arrogancy, and the evil way, and the froward mouth, do I hate” (Proverbs 8:13).

“Therefore ye shall keep these secret plans of their oaths and their covenants from this people, and only their wickedness and their murders and their abominations shall ye make known unto them; and ye shall teach them to abhor such wickedness and abominations and murders; and ye shall also teach them that these people were destroyed on account of their wickedness and abominations and their murders” (Alma 37:29).

There were many “who were made pure and entered into the rest of the Lord their God”  (Alma 13:12).