Sforno on Exodus 32:29/ספורנו על שמות ל״ב:כ״ט

1'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!

2כי 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.”