Mitzvah 375-376) That a Nazirite may not enter the room of a dead body, nor make himself impure even for his father and mother
“He may not come unto the soul of a dead person… he may not make himself impure for his father and his mother, his brother or his sister!” (Bamidbar 6:6-7)
It is a negative commandment that a Nazirite may not enter the room of a dead body, as it says “He may not come unto the soul of a dead person!”
It is likewise a negative commandment that he may not allow himself to become impure for any dead person, not even for his relatives, as it says “He may not make himself impure for his father and his mother, his brother or his sister in their deaths, for the consecration to Hashem is on his head!”. The reason for the enormous severity of the Nazirite that he is commanded not to allow himself to become impure even for his parents, whereas a regular priest, even though he is holy, may become impure for his seven close relatives, is that the sanctity of the priest came about as a result of his status at birth and not as a result of any decision or undertaking that he made. The way he interacts with his relations is therefore the same as any normal person, as a priest is no different from anyone else, apart from the fact that the priest is obligated to serve Hashem in the temple from time to time. There will also be periods when he can live in his tent and be happy and rejoice with his friends and relatives, in which case he will become very close to him and he to them. Hashem therefore allowed him to become impure for them, for the ways of the Torah are pleasantness and all of its paths are peace.
However, the man who becomes a Nazirite for Hashem, for all the days of his vow he is sanctified to Hashem, as the verse testifies “For the crown of Hashem is on his head!”, and he may therefore not defile himself with the pleasures of this world, nor may he be found in the drinking places and in friendly meals, for his separation from wine proves that he has decided to prepare himself and afflict himself before Hashem, and to repair the ways of his soul, to leave aside the pleasures of the dark body. Once he has put all of his heart and intentions towards his precious soul, and has abandoned the needs of body, why should he be interested in the company of his friends? There is no doubt whatsoever that with the elevation of his soul, the bodily pleasures will become worthless in his eyes, and he will definitely not turn towards the company of other human beings, be they related to him or not. He will find no pleasure in anything other than his holy service that he is attached to and his eyes will be permanently on it. This is why the Torah considers that due to his great holiness and unworldly ways, he may not become impure even for his relatives. This is similar to the high priest, who by being so elevated from his brothers, and so separated from the group of loved ones, when all of his thoughts and intentions are only for the service of Hashem, the Torah forbade him from becoming impure even for one of his close relatives. One may not ask, that since a Nazirite will soon finish the days of his vow and become like a normal person and chase after the pleasures of the world, so why now should he be better than a normal priest? The answer is that once a person has separated himself for Hashem once, there is hope that he will sanctify himself and add to his own goodness every day, and heaven will help him, as Chazal said that “One who comes to purify himself receives heavenly assistance!”, and even by being a Nazirite for one day helps towards finishing all of his days in purity.
This prohibition applies in all places and at all times, both to men and to women.