'בהעלותך וגו, seeing that this is a procedure which is repeated daily it is mentioned here. Even though the Tabernacle had been completed, all the work had been done, the menorah was incomplete inasmuch as in order to remain functional the oil and the wicks had to renewed on a regular basis, and the lighting of the flame was required as an ongoing procedure on a daily basis.

אל מול פני המנורה, he was inclining the tips of the wicks on all seven lamps in the direction of the table to provide illumination for its surface.

והעבירו, the vocalisation ve-he-eviru means that it is a modified version of the future tense known as vav hahipuch, the letter ו reversing the tense. Had the vocalisation been veha-aviru it would have been an imperative mode, just as in Exodus 8,4 העתירו אל ה', “plead with the Lord!”

והנפת אותם, Aaron waved them first, followed by Moses. (compare verse 11)

ויתחטאו, as per the instruction in verse 7:הזה עליהם מי חטאת, “sprinkle on them of the waters containing the ash of the read heifer.”

זאת אשר ללוים, this is a new commandment which had not been mentioned elsewhere. Both in Bamidbar and in Nasso G’d had instructed to appoint the Levites to their respective tasks of carrying, etc. from the age of thirty. The number 25 had not been mentioned at all. Here we are told that even though Levites below the age of 30 were not considered as mature enough physically for “active duty,” they were enlisted for “passive duty,” i.e. guard duty which did not require physical exertion, already from the age of twenty-five. This will be spelled out a little later.

מבן עשרים שנה ומעלה יבא לצבא בעבודת אהל מועד; guard duty, as will be explained immediately. ושרת את אחיו לשמר משמרת.

ומבן חמשים שנה ישוב מצבא העבודה של משא, as soon as he has attained the age of fifty he will retire from the duties of carrying parts of the Tabernacle.

The words ולא יעבוד עוד בצבא are to be understood as referring both to the ones younger than 30 and the ones above the age of 50, i.e. both groups not having to performing the physically strenuous type of service. What then were they to do with their time? They were to render service in the form of guard duty, i.e. בשמרותם. The words ככה תעשה ללוים במשמרותם are to be understood as referring to the “training” period of 5 years between their reaching the age of 25 and their attaining the age of 30 when they would assume “active” duties.

(1) THEY MAY ASSIST/SERVE -- both groups -- THEIR BROTHER LEVITES ... BY STANDING GUARD, BUT THEY SHALL PERFORM NO LABOR.

(2) THUS YOU SHALL DEAL WITH THE LEVITES IN REGARD TO THEIR DUTIES. Five years before the 30th year and from age 50 on they shall be commanded regarding the guarding of the Mishkan.