Yevamot

from the first cited text:  Since  Scripture could have used the expression, Thou shalt make thee fringes,  what need was there for that of 'twisted cords'? Consequently it must have been intended for the purpose of allowing that text to be used for the deduction.  But this  is required for the determination of the number [of threads, thus]:  'Twisted cord' implies two threads,  [and so] 'twisted cords'  implies four threads, therefore,  one twisted cord is to be made [of the four] and from the middle of it separate threads  are to hang down!  — If so,  Scripture should have stated, Thou shalt not wear a mingled stuff wool and linen:  what need was there to add 'together'?  Consequently it must have been intended for the purpose of allowing a free text for the deduction.  But this text too  is required for the deduction that two stitches  form a combination  and that one stitch does not! — If so, the All Merciful should have written, Thou shalt not wear wool and linen together; what need was there for inserting 'mingled stuff'? Hence it must be concluded that the purpose was to allow a free text for deduction.  But is not this text  still required [for the deduction that 'mingled stuff'  is not forbidden] unless it was hackled, spun and twisted?  — But [the fact is that] all this is deduced from the expression of 'mingled stuff'. So far it has been shewn that a positive precept supersedes a mere prohibition;  where, however, do we find that it supersedes also a prohibition involving kareth,  and that in consequence [the explicit expression] ''aleha'  should be required to forbid it?  And if it be replied that this  might be deduced from circumcision,  [it may be retorted]: Circumcision stands in a different category,  for concerning it thirteen covenants  were made!  From the paschal lamb?  — The paschal lamb also stands in a different category  since it too involves kareth!  From the daily offering?  — The daily offering also stands in a different category  since it is also a regular [offering]!  [Now though] it  cannot be derived from one  it might be derived from two. From which shall it be derived? [If the reply is]: Let it be derived from circumcision and the paschal lamb, [it may be retorted]: These also involve kareth.  From the paschal lamb and the daily offering? — Both are also intended for the Most High.  From circumcision and the daily offering? — Both were also in force before the giving of the law,  this being according to the view of him who holds that the burnt-offering which Israel offered in the wilderness was the daily burnt-offering.  Nor [can the derivation be made] from all of them, since they were all in force before the giving of the law. But [this is the reason for] the need of a special text:  It might have been assumed  that this  should be derived from the precept of honouring one's father and mother; for it was taught: Since one might have assumed that the honouring of one's father and mother should supersede the Sabbath, it was explicitly stated, Ye shall fear every man his mother and his father, and ye shall keep My Sabbaths,  it is the duty of all of you  to honour Me. Now is not the case in point one where the parent said to him, 'Slaughter for me',  or 'Cook for me';  and the reason [why the parent must not be obeyed is] because the All Merciful has written, 'Ye shall keep my Sabbaths',  but had that not been so  it  would have superseded?  — No;