God told Moses to declare the following to Aaron's descendants, the priests:
Let no [priest] defile himself [by contact with] the dead among his people,
Vayomer Adonay el-Moshe emor el-hakohanim beney Aharon ve'amarta alehem lenefesh lo-yitama be'amav.
||except for such close blood relatives as his mother, father, son, daughter or brother.
Ki im-lish'ero hakarov elav le'imo ule'aviv velivno ulevito ule'achiv.
||He may also allow himself to become ritually unclean for his [deceased] virgin sister, who is [also] close to him as long as she is not married.
Vela'achoto habetulah hakrovah elav asher lo-hayetah le'ish lah yitama.
||[However,] a husband may not defile himself for his [dead] wife if she is legally unfit for him.
Lo yitama ba'al be'amav lehechalo.
See Numbers 19:14.
|close to him|
This is a sister who has the same father as the priest (Yevamoth 22b; Yad, Avel 2:1).
|a husband may not...|
(Sifra; Rashi). Or, 'a man may not defile himself for a corpse among his people' - when there are others to care for it (Rashi). Or, 'a man may not defile himself, even for the great' (Saadia; Baaley Tosafoth). Or, '[Since he is] a leader, he shall not be defiled among his people' (Targum).
|if she is legally unfit...|
See Leviticus 21:7 (Yevamoth 22b; Rashi; cf. Targum Yonathan.) Or, 'since it makes him unfit for service' (Rashi; Rashbam).