Yevamot

This  is satisfactory according to the view of the Tanna of the School of R. Ishmael;  as to the Rabbis,  however, how do they arrive at the deduction?  — They derive it from his head;  for it was taught: [Scripture stated], 'His head';  what need was there for it?  — Whereas it has been stated, Ye shall not round the corners of your head,  one might infer that [this law  applies to] a leper also, hence it was explicitly stated, his head;  and this Tanna is of the opinion that rounding all the head is also regarded as 'rounding'.  This [conclusion, however,] may be refuted: The reason why the prohibition of  'rounding' [may be superseded is] because it is not applicable to everybody!  — But [the inference] is derived from his beard;  as it was taught: 'His beard';  what need was there for stating it?  — Whereas it was said, Neither shall they shave off the corners of their beard,  one might infer that this prohibition applies also to a leprous priest,  hence it was explicitly stated, 'his beard'.  And since there is no object in applying it to a prohibition which is not incumbent upon everybody,  let it be applied to a prohibition which is incumbent upon all.  But this  is still required [for its own context]! For since it might have been assumed that as priests are different from [other people]. Scripture having imposed upon them additional commandments, and so even a prohibition which does not apply to everybody is not superseded in their case; [therefore] it was necessary to teach us that it does supersede.  — In truth the inference comes from 'his head' [in the manner deduced by] the following  Tanna. For It was taught: His head:  what need was there for mentioning it?  Whereas Scripture had stated, There shall no razor come upon his head,  one might infer that the same prohibition is applicable to a leprous nazirite  also, hence it was explicitly stated, 'his head'.  This,  however, may be refuted: The reason why a [leprous] nazirite [may shave his head] is because he is also in a position to obtain absolution.  For, were not this the reason,  what then of the accepted rule,  that no positive precept may supersede a negative and positive precept combined; why not deduce the contrary from the law  of the [leprous] nazirite?  Consequently, [it must be conceded that] the reason why no deduction may be made [from the law of the nazirite is] because it may be refuted [on the grounds] that in his case absolution is possible; so here also the refutation may be advanced, 'Since in his case absolution is possible'!  — The deduction, in fact, is made