Nazir

But surely this is needed to tell us [the plain fact] that he may not defile himself for his father?  — In point of fact, 'for his father' tells us that he may not defile himself for his father;  'for his brother'  he may not defile himself but he may defile himself for a corpse [the burial of] which is a religious duty; 'or for his mother'  is used to form the basis of a Gezerah shawah after the manner of Rabbi;  whilst 'or for his sister'  is required for the following [teaching]. For it has been taught: For what purpose is 'for his sister' mentioned?  If a [nazirite] was on his way to slaughter his Paschal lamb, or to circumcise his son and he heard that a near kinsmen had died, it might be thought that he ought to defile himself. It therefore says, 'He shall not make himself unclean'. But it might [then] be thought he should not defile himself for a meth mizwah. The text therefore adds, 'for his sister', [implying that] for his sister he is forbidden to defile himself, but he may defile himself for a meth mizwah. R. Akiba said:  ['Nefesh'] 'body' refers to strangers; 'dead' to kinsmen, 'For' his father or for his mother' [teaches that] he is forbidden to defile himself for these, but he may defile himself for a meth mizwah. 'For his brother' [tells us] that if he he both High Priest and a nazirite, it is for his brother that he is forbidden to defile himself, but he may defile himself for a corpse [the burial of] which is a religious duty. 'For his sister' [is required] as has been taught: 'If a man was on his way to slaughter his Paschal lamb or circumcise his son etc.' Whence does R. Akiba derive the lesson learnt by Rabbi from the Gezerah shawah? — He will reply: Since it has been said that if he be both High Priest and a nazirite it is for his brother that he is forbidden to defile himself but he may defile himself for a meth mizwah,  what difference does it make whether he is simply High Priest or High Priest and a nazirite. And whence does R. Ishmael derive the rule about a High Priest who is a nazirite?  — Since the All-Merciful allows [the breach of] a single prohibition in connection with a meth mizwah, what does it matter whether there is only one prohibition or two? [In that case] for what purpose is for his sister required?  — You might assume that in connection with a meth mizwah the All-Merciful permitted [the defilement of] a nazirite and a priest because this is an offence which is merely prohibited but where the neglect of circumcision and the Paschal lamb entailing kareth  is involved, [the nazirite or priest] should not defile himself for a meth mizwah  and so we are told [that he should].