דברי הימים א, פרק כ״ג, פסוק כ״ח

The daily operations of the Temple required a highly organized division of labor to ensure the holy work proceeded properly. The Levites served as the essential operational and logistical backbone that supported the entire system. Their fundamental role was to work directly under the authority of the Priests, assisting them in their daily duties [רש״י, מצודת דוד]. Because these support tasks, while numerous, were not the most central duties of the Temple, they were assigned to younger Levites starting at the age of twenty. The primary responsibilities, such as singing and guarding the gates, were reserved for older Levites from the age of thirty [מצודת דוד, מלבי״ם].

Stationed throughout the courtyards and chambers of the Temple complex, the Levites were responsible for maintaining overall order and cleanliness [מצודת דוד, ביאור שטיינזלץ]. A crucial part of this upkeep was the preservation of strict purity, which involved two complementary actions. First, they actively stood guard to prevent anything impure from entering and defiling the holy items [מצודת דוד, ביאור שטיינזלץ]. Second, if the Temple grounds or its vessels ever became defiled, the Levites were called upon to purify the area and remove the impurity, a duty they carried out during the reign of King Hezekiah [רש״י, רד״ק]. However, their authority to remove impurity was strictly limited to the outer courtyards and chambers. If impurity reached the inner sanctuary of the Temple, clearing it out was a duty restricted entirely to the Priests [מלבי״ם].

Beyond these specific tasks, the Levites bore a general responsibility for the remaining operational routines of the Temple [מצודת דוד, ביאור שטיינזלץ]. They stood constantly prepared and ready to handle the ongoing work of God's house across all its logistical levels [רד״ק].