At the end of a Nazirite's vow of dedication, the Torah commands a specific act: shave the head, and do it "at the door of the tent of meeting" (Numbers 6:18). Read literally, that is a strange place for a haircut.
The Rabbis of Sifrei Bamidbar, the tannaitic halakhic midrash on the Book of Numbers, will not let the verse be read literally. Their working argument is that the dignity of the sanctuary forbids it. Even the priests are warned in (Exodus 20:23) not to ascend the altar by steps, lest their bodies be exposed. Public shaving at the entrance, by that standard, is unthinkable.
So the Sifrei moves the verse sideways. "At the door of the tent of meeting," the Rabbis argue, names the location of the peace-offering, not the location of the haircut. (Leviticus 3:2) uses the same phrase for the slaughter of peace-offerings. The verse, in this reading, is dating the shaving rather than placing it. The Nazirite shaves after the peace-offerings have been brought.
Rabbi Yitzchak doubles down. The phrase speaks of the peace-offerings. But the careful Talmudic mind keeps testing. What if the verse is literal? What if shaving does belong at the door? The Sifrei closes the loop with another verse from (Numbers 6:18): "and he shall take the hair of the head of his Naziritism." In the same place where the peace-offerings are cooked, there shall he shave. The room is the cooking room, not the public threshold.
Abba Channan, citing Rabbi Eliezer, adds one further qualification. The verse holds only when the door is actually open. If the door is closed, no shaving. The geography is conditional, not absolute.
The hair itself gets a parallel ruling. The verse continues: "and he shall place it on the fire which is under the sacrifice of the peace-offerings." The Rabbis ask whether this applies only to peace-offerings, or whether the hair of a Nazirite who has also become impure can be burned under the sin-offering and guilt-offering. The phrase "under the sacrifice," the Sifrei teaches, is general enough to cover any of them. The same generalization handles the question of whether the hair can be placed on a fire outside the sanctuary. "He shall place it on the fire" extends the rule.
The whole passage is a single rabbinic motion. A verse that would have produced an undignified literal practice is read as a temporal marker, a relocation to the cooking room, a conditional opening of the door, and a generalization of the fire. None of the Torah's words are discarded. Every phrase is rotated until the practice it describes is one a community could actually perform with reverence.