Exodus 32:29

And Mosheh said, Offer your oblation for the shedding of the blood that is upon your hands, and make atonement for yourselves before the Lord, because you have smitten a man his son or his brother, and that you may bring a blessing upon you this day.

מלאו ידכם היום, “dedicate yourselves this day!” as if the line had been written in the past tense, as if the word כי had preceded the word מלאו, expressing approval of their loyalty. Rallying to the call of Moses and carrying out his instructions was equivalent to offering a sacrifice to G’d.

איש בבנו ובאחיו, you have extended your hands towards heaven, i.e. in support of the interests of G’d.

'מלאו ידכם היום לה, acquire for yourselves some degree of perfection today! Today you will become worthy to perform service in G’d’s Temple in the future!

כי איש בבנו ובאחיו, for each one of you have already become sanctified to G’d through having circumcised his own son for G’d, something you did in the desert. (according to Sifrey Behaalotcha,15, the tribe of Levi were the only ones who observed this commandment while the people were in the desert). [how many Levites could have been circumcised during the 89 days since the Passover and the return of Moses from Mount Sinai? Ed.] Therefore, מלאו ידכם prove this sense of loyalty again by becoming blessed through assuming this difficult task of carrying out His instructions now. ובאחיו, and today you have again demonstrated your loyalty of spilling the blood of even your own brothers. Moses gave recognition to this collective act of loyalty to G’d in preference to loyalty to their fellow Jew in Deuteronomy 33,9-11 when he said about this tribe:כי שמרו אמרתך ובריתך ינצורו,.... ברך ה' חילו ופעל ידיו תרצה, “for they have observed Your word and Your covenant they preserved. Bless, Hashem, his resources and favour the works of his hand.”

ולתת עליכם היום ברכה, “so that he may bestow a blessing on you this day.” From this day on the blessings that Moses bestowed on the Levites as described in Deuteronomy 33,8 additionally, although Yaakov had failed to bless them on his deathbed became effective, just as Moses blessed Reuven, although Yaakov had failed to bless him. He received a blessing from Moses although he did not receive it from his father Yaakov, as in the meantime his descendants had volunteered to be the vanguard of the army of the Israelites when they conquered the land of Canaan and they did not return to their families for 14 years until all the tribes had received their ancestral lands.