4,020. A Chalal

Hilchos Bias HaMikdash 6:10

If a kohein performed the service and it was later found that he was a chalal,* the service he performed in the past remains valid, but he may no longer serve going forward. If he nevertheless serves, the service is not profaned. This is inferred from Deuteronomy 33:11: “Hashem will bless His legion and accept the work of its hand,” meaning that He will accept it even from the “defrocked”** among them.

Hilchos Bias HaMikdash 6:11

The Sanhedrin sat in the Chamber of Hewn Stone. Their main ongoing job was to sit and rule on matters of the priesthood, to investigate the lineage of the kohanim and to inspect their blemishes. If some disqualification was found in a kohein’s lineage, he would put on black clothes, wrap himself in black and leave the courtyard. If a kohein was found to be unblemished and of unblemished lineage, he would put on white clothes and enter to serve with his fellow kohanim.

*The offspring of a kohein with a woman prohibited to him. A chalal is not considered a kohein.

**For want of a better term.