'Clothed in White' in the Bible

and the Levites, the singers, to all of them, to Asaph, to Heman, to Jeduthun, and to their sons, and to their brethren, clothed in white linen, with cymbals, and with psalteries, and harps, are standing on the east of the altar, and with them priests, to a hundred and twenty, blowing with trumpets --

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