Rashi on Exodus 38:21/רש"י על שמות ל״ח:כ״א

1אלה פקודי THESE ARE THE SUMS [OF THE TABERNCLE] — In this section are enumerated all the weights of the metals given as a contribution for the Tabernacle, of silver, gold and copper, and also there are enumerated the vessels used for every kind of service in it.

2המשכן משכן OF THE TABERNACLE, EVEN OF THE TABERNACLE — The word משכן is mentioned here twice in allusion to the Temple that was taken in pledge (משכן) — as it were — (as a security for Israel’s repentance) by being twice destroyed for Israel’s iniquities (Midrash Tanchuma, Pekudei 5).

3משכן העדת THE TABERNACLE OF THE TESTIMONY — The Tabernacle was a testimony to Israel that God had shown Himself indulgent to them in respect to the incident of the golden calf, for through the Temple He made His Shechinah dwell amongst them (Midrash Tanchuma, Pekudei 6).

4עבדת הלוים THE SERVICE OF THE LEVITES — The things in the Tabernacle which were counted and its vessels constituted the service entrusted to the Levites in the wilderness — to carry them, to take them down and to set them up, each man according to the burden which was assigned to him, as is set forth in the section נשא (Numbers 4).

5ביד איתמר BY THE HAND OF ITHAMAR — He was the officer appointed over them (the Levites) with the duty to hand over to each “house of the father” (בית אב) the service that devolved upon it.