And all its spoil you shall gather into the midst of its open square and burn with fire the city and all its spoil completely for Hashem your God, and it shall be a mound forever; it shall not be rebuilt.
English: “You shall gather… and burn” — Hair of the head is permitted, because it is written “you shall gather and burn” — that which requires only gathering and burning. This excludes that which requires plucking, gathering, and burning.
On the daf / in context: Items that require an extra preparatory step (such as plucking hair) before they can be gathered and burned are excluded from the prohibition.
Type of Learning
Derash on the verse (Sifrei) — excluding hair and similar items from the spoil.
What Is Learned
Hair of the head (and similarly attached fruit) is not subject to the prohibition of the spoil of the wayward city.