The future division of the land of Israel sets aside a unique and special inheritance for a select group of priests. This distinct honor serves as a reward for those who demonstrated absolute loyalty to God during periods of severe national spiritual decline.
There are different perspectives on the exact nature of this designated holiness. One approach suggests that the portion of land itself is uniquely sanctified and specifically reserved for these priests [רש״י, מלבי״ם]. Another perspective maintains that the holiness refers directly to the priests themselves. In this view, they are recognized as a specially sanctified group due to their extraordinary spiritual standing [מצודת דוד, מצודת ציון, רד״ק, ביאור שטיינזלץ].
This profound privilege is awarded to the descendants of Zadok, the High Priest. Throughout turbulent times, these specific priests diligently maintained their responsibilities in the service of God and never abandoned their posts [מצודת דוד]. Because of their uncompromising dedication to the Temple, they alone are deemed worthy to serve within it in the future and to live in its immediate surroundings [מלבי״ם, ביאור שטיינזלץ].
Their unique status is emphasized by their refusal to wander astray. Much like a traveler who becomes lost on a journey [מצודת ציון], the concept of straying here represents falling into idol worship and foreign rituals [מצודת דוד, מלבי״ם, ביאור שטיינזלץ]. The descendants of Zadok held firmly to their faith while the rest of the Israelites fell into idolatry. Their steadfastness is even more remarkable considering that the other Levites, priests who were not from the line of Zadok, also lost their way and actively assisted the people in worshipping idols [רד״ק, מצודת דוד].