'White' in the Bible

I saw until thrones were placed, and one who was ancient of days sat: his clothing was white as snow, and the hair of his head like pure wool; his throne was fiery flames, [and] its wheels burning fire.

Some of those who are wise shall fall, to refine them, and to purify, and to make them white, even to the time of the end; because it is yet for the time appointed.

Many shall purify themselves, and make themselves white, and be refined; but the wicked shall do wickedly; and none of the wicked shall understand; but those who are wise shall understand.