And for his sister a virgin, that is nigh unto him — That is, his maiden sister who still remains in sole relationship with him. What this is the next clause explains more minutely.
Which hath had no husband. — When she is married she goes to her husband, and ceases to be near her brother. It then devolves upon her husband to attend to the funeral rites.
For her may he be defiled. — According to the administrators of the Law during the second Temple, the priest was not only allowed to contract defilement by attending to the funeral rites of these seven relations, but was obliged to do it.