'Clothed in White' in the Bible

The one conquering shall thus be clothed in white garments; and I will not blot out his name from the book of life, and I will confess his name before my Father, and in the presence of his angels.

And around about the throne were twenty-four thrones: and on the thrones twenty-four elders are sitting, clothed in white garments; and upon their heads golden crowns.

After these things I saw, and behold a great multitude, which no one was able to number, out of every nation, and tribes, and peoples, and tongues, standing before the throne, and before the Lamb, clothed in white robes, and palms in their hands;

And one of the elders responded, to me saying, Who are these who are clothed in white robes, and whence came they?