1 Chronicles 23:28-29

28For their duty is to assist [the priests] the sons of Aaron in the service of the house of the Lord, in [caring for] the courtyards, the chambers, the purifying of all holy things, and any work of the service of the house of God,

29and with the showbread, and the fine flour for a grain offering, and unleavened wafers, or what is baked in the pan or what is well-mixed, and all measures of volume and size [as the Law of Moses required].