What does Numbers 6:1-21 mean?

And the LORD spoke to Moses, saying, “Speak to the people of Israel and say to them, When either a man or a woman makes a special vow, the vow of a Nazirite, to separate himself to the LORD, he shall separate himself from wine and strong drink. He shall drink no vinegar made from wine or strong drink and shall not drink any juice of grapes or eat grapes, fresh or dried. All the days of his separation he shall eat nothing that is produced by the grapevine, not even the seeds or the skins. “All the days of his vow of separation, no razor shall touch his head. Until the time is completed for which he separates himself to the LORD, he shall be holy. He shall let the locks of hair of his head grow long. “All the days that he separates himself to the LORD he shall not go near a dead body. Not even for his father or for his mother, for brother or sister, if they die, shall he make himself unclean, because his separation to God is on his head. All the days of his separation he is holy to the LORD. “And if any man dies very suddenly beside him and he defiles his consecrated head, then he shall shave his head on the day of his cleansing; on the seventh day he shall shave it. On the eighth day he shall bring two turtledoves or two pigeons to the priest to the entrance of the tent of meeting, and the priest shall offer one for a sin offering and the other for a burnt offering, and make atonement for him, because he sinned by reason of the dead body. And he shall consecrate his head that same day and separate himself to the LORD for the days of his separation and bring a male lamb a year old for a guilt offering. But the previous period shall be void, because his separation was defiled. “And this is the law for the Nazirite, when the time of his separation has been completed: he shall be brought to the entrance of the tent of meeting, and he shall bring his gift to the LORD, one male lamb a year old without blemish for a burnt offering, and one ewe lamb a year old without blemish as a sin offering, and one ram without blemish as a peace offering, and a basket of unleavened bread, loaves of fine flour mixed with oil, and unleavened wafers smeared with oil, and their grain offering and their drink offerings. And the priest shall bring them before the LORD and offer his sin offering and his burnt offering, and he shall offer the ram as a sacrifice of peace offering to the LORD, with the basket of unleavened bread. The priest shall offer also its grain offering and its drink offering. And the Nazirite shall shave his consecrated head at the entrance of the tent of meeting and shall take the hair from his consecrated head and put it on the fire that is under the sacrifice of the peace offering. And the priest shall take the shoulder of the ram, when it is boiled, and one unleavened loaf out of the basket and one unleavened wafer, and shall put them on the hands of the Nazirite, after he has shaved the hair of his consecration, and the priest shall wave them for a wave offering before the LORD. They are a holy portion for the priest, together with the breast that is waved and the thigh that is contributed. And after that the Nazirite may drink wine. “This is the law of the Nazirite. But if he vows an offering to the LORD above his Nazirite vow, as he can afford, in exact accordance with the vow that he takes, then he shall do in addition to the law of the Nazirite.”