2 Chronicles 29:15 (KJV)

And of the sons of Elizaphan; Shimri, and Jeiel: and of the sons of Asaph; Zechariah, and Mattaniah:

And of the sons of Heman; Jehiel, and Shimei: and of the sons of Jeduthun; Shemaiah, and Uzziel.

And they gathered their brethren, and sanctified themselves, and came, according to the commandment of the king, by the words of the Lord, to cleanse the house of the Lord.

And the priests went into the inner part of the house of the Lord, to cleanse it, and brought out all the uncleanness that they found in the temple of the Lord into the court of the house of the Lord. And the Levites took it, to carry it out abroad into the brook Kidron.

Now they began on the first day of the first month to sanctify, and on the eighth day of the month came they to the porch of the Lord: so they sanctified the house of the Lord in eight days; and in the sixteenth day of the first month they made an end.