Numbers 6:9
And if any man die very suddenly by him, and he hath defiled the head of his consecration; then he shall shave his head in the day of his cleansing, on the seventh day shall he shave it.
Cross-references
Numbers 6:18 describes shaving the head at the completion of the Nazirite vow, paralleling the defilement shaving here — both require shaving.
In Numbers 19:14-19, the general purification from dead bodies (ashes and sprinkling) parallels the Nazarite's cleansing procedure here.
Acts 21:23 describes Paul undergoing purification with four men under a vow, directly referencing the Nazirite purification process here.
Acts 21:24 mentions shaving the head as part of the Nazirite vow completion, echoing the defilement shaving here.
Leviticus 14:9 also requires shaving head, beard, and eyebrows on the seventh day for leper cleansing — strongly parallels the seventh-day shaving here for Nazirite defilement.
Both require a sin offering after defilement from a dead body before re-entering sacred service — here for priests, there for Nazirites.
In Acts 18:18, Paul cuts his hair because of a vow, likely a Nazirite vow, showing the ongoing practice of this OT ritual.