Nazir 39 - The direction of hair growth
If a nazir shaves his head - or if bandits grabbed him and shaved it - he will have to wait at least thirty more days before concluding his term. This is because the standard (and the minimal) term is thirty days, and when he shaves his hair, it must have at least thirty days of growth.
A question: is the hair growing from the root or from the end? Why would we want to know? - If the hair is growing from its root, and the bandits gave him a haircut but left seven days worth of hair growth on his head - does he now wait for thirty day still, or only for twenty-three? For example, if the hair grows from the root, then that hair which he consecrated has grown down by now, and was cut by the bandits, so he will have to wait another thirty days. But if the hair grows from the end down, then he will only need twenty three days. So?
Let's look at a nit (louse). It always remains at the root - so it must be that the hair grows from the end! - Not so fast! Maybe the nit is alive and keeps crawling to the root. Well, let's look at a dead nit - it is always found at the end of the hair, so it must grow from the root! - No, because perhaps when the nit is dead and cannot resist gravity, it keeps sliding down as the hair grows.
The final proof comes from beards of old men who die them black. We see that the whitish color of gray hair appears at the root - so it is proven that the hair grows from the root!
Art: Portrait of a bearded old man by Rembrandt Van Rijn