"The allusion seems to be to the custom of the Jewish sanhedrim in judging of priests fit for service:
they examined the priests concerning their genealogies and blemishes; every priest in whom was found anything faulty in his genealogy, he was clothed in black and veiled in black, and went out of the court; but everyone that was found perfect and right, 'he was clothed in white,' and went in and ministered with his brethren the priests."
(The New John Gill's Exposition of the Entire Bible)
Please be advised that this domain (Philologos.org) does not endorse 100 per cent any link contained herein. This forum is for the dissemination of pertinent information on an end-times biblical theme which includes many disturbing, unethical, immoral, etc. topics and should be viewed with a mature, discerning eye.