To have one’s garments made white in the blood of the Lamb is to be made free from sin and its effects, this through sincere repentance and submission to the will of the Master.
It is to be cleansed and sanctified, to be made pure and holy-fit to dwell in the presence of God and angels. Such a state comes through subscribing to the ordinances of the gospel and thereafter yielding one’s heart unto God. (See Alma 13:12; Helaman 3:35; 3 Nephi 27:19-20; Moses 6:59-60.)
These are persons whose garments are free from the blood (sins—2 Nephi 9:44) of the world because of the blood of him who overcame the world, “they which came out of great tribulation, and have washed their robes, and made them white in the blood of the Lamb” (Revelation 7:14).