Numbers 6:11 (BSB)

And the priest is to offer one as a sin offering and the other as a burnt offering to make atonement for him, because he has sinned by being in the presence of the dead body. On that day he must consecrate his head again.

From Numbers 6. Also in the ESV.

Commentary on Numbers 6:11

• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on Numbers 6:1-21: After the law for the discovery and shame of those that by sin had made themselves vile, fitly follows this for the direction and encouragement of those who by their eminent piety and devotion had made themselves honourable, and distinguished themselves from their neighbours.
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on Numbers 6:11: And he shall consecrate unto the Lord the days of his separation,.... He was to begin his account again, from the time of his shaving his head, and devote as many days to the service of the Lord as what he had vowed before: and shall bring a lamb of the first year for a trespass offering; we see how much trouble and expense were...
• Geneva Bible Notes (Reformed), Geneva Bible Study Notes on Numbers 6:11: And the priest shall offer the one for a sin offering, and the other for a burnt offering, and make an atonement for him, for that he sinned by the dead, and shall hallow his head that same day. (e) By being present where the deceased was.
• Keil & Delitzsch (Lutheran), Biblical Commentary on the Old Testament on Numbers 6:9-11: Num 6:9-11 But if any one died suddenly in a moment “by him” (עליו, in his neighbourhood), and he therefore involuntarily defiled his consecrated head, he was to shave his head on the day of his purification, i.e., on the seventh day (see Num 19:11, Num 19:14, Num 19:16, and Num 19:19), not “because such uncleanness was more especially caught and retained by the hair,”...