במדבר, פרק ז׳, פסוק כ״ב

The selection of an animal for a sin offering is never a random choice; rather, it carries deep symbolic meaning. The specific use of a male goat serves to atone for a dark moment in the history of the family: the selling of Joseph. After the brothers sold him, they slaughtered a goat and dipped Joseph’s coat in its blood to deceive their father. By bringing this exact animal as an offering, the act serves as a direct spiritual repair for that early deception and sin [רש״י].