In these verses, Alma emphasized by way of repetition, that the many who were ordained High Priests were so set apart to that high and holy calling because of their great faith and on account of their willingness to repent which, after all, is the never-failing sign of humility. Such a one renders himself amenable to the promptings of that "still small voice" which comes from the Father "to lead, and to direct, and to warn of things to come." He is ready, at all times, to submit, or yield without hesitation to the demands of the Holy Spirit although he may not understand its purpose. He chooses to walk in the ways of righteousness rather than work the works of darkness.
Therefore, Alma said that they were sanctified, or made holy. Their sins, because of their righteousness were forgiven; through the Atonement of Christ they stand spotless and pure before God's throne, and in robes that are made white through the Blood of the Lamb they have entered into the rest of the Lord their God.
Speaking of the Sanctified, we are reminded that they were healed of their iniquity, which also reminds us of the words of God's holy Prophet, who spoke for the Lord, "I, even I, am He that blotteth out thy transgressions for Mine own sake, and will not remember thy sins." (Isaiah 43:25)