'Clothed in White' in the Bible

He that overcometh shall be clothed in white raiment; and I will not blot out his name from the book of life; but I will own his name before my Father, and before his angels.

And around the throne were four and twenty seats: and upon the seats I saw twenty four elders sitting, clothed in white garments; and they had upon their heads crowns of gold.

After this I beheld, and lo, a great multitude, which no one could number, out of all nations, and tribes, and people, and languages, standing before the throne and before the Lamb, clothed in white robes, and with palms in their hands;

And one of the elders said unto me, Who are these that are clothed in white robes, and from whence did they come?