Mishnà su Deuteronomio 18:5

On the south were the wood chamber, the chamber of the exile and the chamber of hewn stones. The wood chamber: Rabbi Eliezer ben Jacob says: I forget what it was used for. Abba Shaul says: It was the chamber of the high priest, and it was behind the two of them, and one roof covered all three. In the chamber of the exile there was a fixed cistern, with a wheel over it, and from there water was provided for all of the courtyard. In the chamber of hewn stone the great Sanhedrin of Israel used to sit and judge the priesthood. A priest in whom was found a disqualification used to put on black garments and wrap himself in black and go away. One in whom no disqualification was found used to put on white garments and wrap himself in white and go in and serve along with his brother priests. They used to make a feast because no blemish had been found in the seed of Aaron the priest, and they used to say: Blessed is the Omnipresent, blessed is He, for no blemish has been found in the seed of Aaron. Blessed is He who chose Aaron and his sons to stand to minister before the Lord in the Holy of Holies.