Chasidut zu Bamidbar 8:19

Numbers 8,19. “I have given the Levites, etc.;” this ‎sounds strange as in the previous verse G’d had spoken of having ‎‎“taken” the Levites, i.e. ‎ואקחה את הלוים‎. According to Rashi ‎on the verse commencing with ‎ואתנה את הלוים‎, the words ‎בני ‏ישראל‎ occur five times in this paragraph to show how fond G’d ‎was of the Children of Israel. Rashi adds that he has copied ‎this interpretation from Vayikrah Rabbah. When a person ‎has a choice of selecting one item from amongst many similar ‎ones, this is proof that he liked the one he chose more than the ‎others. If G’d chose the Levites from all the tribes of Israel for ‎special tasks, this is proof that He liked this tribe best of all. There ‎was a suspicion that the fact that G’d chose the Levites would be ‎interpreted as proof that G’d did not like the other tribes. This ‎prompted the Torah to mention the other tribes five times, as ‎proof that G’d loved all the tribes of Israel. If He nonetheless ‎chose the Levites for special tasks it was only so that they could ‎serve as an instrument to atone for the sin of the golden calf, a ‎sin in which none of the Levites had participated.‎
We find something puzzling when perusing the sequence of ‎the offerings used in the process of purifying the Levites. In verse ‎‎8 when the offerings are prepared, the burnt offering, ‎עולה‎ is ‎mentioned ahead of the sin offering, ‎חטאת‎, whereas when ‎presentation of these two offerings is reported (verse 12) we find ‎that the sin offering is mentioned first.‎