Commento su Numeri 7:9

כי עבדת הקדש עלהם [BUT TO THE SONS OF KOHATH HE GAVE NONE (NO WAGGONS)] BECAUSE THE עבדת הקדש BELONGS UNTO THEM — (not the service of the Sanctuary devolved upon them, but the service in connection with) carrying the most holy objects: the ark, the table, etc. was incumbent upon them, therefore בכתף ישאו they should carry upon their shoulders (not in wagons).

ולבני קהת לא נתן כי עבודת הקודש עליהם, as opposed to what was called עבודת אהל מועד. G’d had commanded concerning these carts that they would form part of what was called עבודת אהל מועד, the task of the members of the family of Gershon and that of the family of Merari. The Kehatites did not transport anything which was part of the actual structure called משכן. They only transported furnishings which were part of the Tabernacle. Those were referred to as מקדש for short. (compare Numbers 10,21 ונשאו הקהתים נושאי המקדש.)

V. 9. כי עבודת הקדש עליהם, im Gegensatz zu עבדת אהל מועד im engeren Sinne des V. 5. Ihnen lag der Dienst des קדש im eigentlichen Sinne ob, jener Gegenstände, die die eigentlichen Objekte bilden, für welche das אהל מועד errichtet worden. Sie sind das eigentlich Heilige, durch dessen Heiligkeit alle anderen Heiligtümer ihre Heiligkeit erhalten, sie sind das קדש der קדש הקדשים ,קדשים, wie sie Kap. 4, 4 genannt werden. Sie sind dasjenige קדש, in welchem die ganze von uns zu lösende Aufgabe ihren Ausdruck hat, für welche wir daher die eigenste Kraft unseres Wesens einzusetzen haben, daher: בכתף ישאו

That is that He commanded the priests to carry the ark on their shoulders, when we want to move it from place to place. And that is His saying, "they bore it on their shoulders" (Numbers 7:9). Even though this command came to the Levites at that time, that was in fact because of the paucity (at that time) of priests who were [actually] obligated with the commandment. If so, the commandment is obligatory on the priests; and they would be the ones to carry it, as it is explained in the Book of Joshua (Joshua 3:6) and in the Book of Samuel (II Samuel 15:25). And when David commanded that the ark be carried the second time, he said in Chronicles (I Chronicles 15:15), "The Sons of Levi carried the Ark of God by means of poles on their shoulders, as Moshe had commanded, in accordance with the word of the Lord." And likewise when it mentions the divisions of the priests into twenty four watches in Chronicles, it states (I Chronicles 24:19), "According to this allocation of offices by tasks, they were to enter the House of the Lord according to the ordinance given to Aharon their father, as the Lord, God of Israel, had commanded him." The Sages, may their memory be blessed, explained that this hints to the service of the priests being to carry the ark on the shoulder. And that is (what is meant by), "as the Lord, God of Israel, had commanded him." And the language of Sifrei is "'According to the ordinance, etc., as the Lord had commanded him' - where did He command him? 'But to the Sons of Kehat he did not give any; since theirs was the service of the [most] sacred objects, they bore it on their shoulders.'" Behold it has been made clear to you that this commandment is included in the commandments. (See Parashat Nasso, Mishneh Torah, Vessels of the Sanctuary and Those who Serve Therein 2.)