His statement, “the nails,” includes the fingernails and toenails.
His statement, “Whoever shaves or trims three is liable to a compensatory sacrifice”: “whoever” is a conditional noun that renders the verb apocopated; “shaves” is the verb of the condition; “trims” is coordinated with the verb of the condition; and “is liable to a compensatory sacrifice” is the result clause. That is, any person in a state of consecration who shaves three hairs is liable to a compensatory sacrifice, or who trims three nails is liable to a compensatory sacrifice, because the minimum number denoted by a plural is three. If the minimum plural is three, then shaving three hairs truthfully qualifies as having shaved hair. Remarkably, the jurists say that if he cuts three hairs from his head, he has not exited the state of consecration, yet they treat three hairs as equivalent to shaving!
It is understood from his statement, “three, then he is liable to a compensatory sacrifice,” that if he trims or shaves fewer than that, he is not liable to a compensatory sacrifice. Yet they said that for every hair he must feed one needy person, and for every nail he must feed one needy person (1). This detailed distinction requires evidence. Where in the sunnah is there evidence that a single hair requires feeding one needy person, or that a single nail requires feeding one needy person?
For this reason, the scholars differed concerning the amount for which the expiation becomes obligatory, holding several views:
The first view—and the authoritative position of the school—is that it applies to three or more.
The second view is that if he shaves four hairs, he is liable to a compensatory sacrifice.
The third view is that if he shaves five hairs, he is liable to a compensatory sacrifice.
The fourth view is that if he shaves a quarter of his head, he is liable to a compensatory sacrifice.